The Longest Blooming Perennial of All?

Abundant whitish flowers over deeply cut leaves of white corydalis

White corydalis: the perennial that won’t stop blooming. Photo: Michel Descamps, Sysbio

The older I become, the more I appreciate plants that cover the entire blooming season. Yes, I have grown and still grow lots of plants with a 2- or 3-week blooming period and enjoy trying to mix and match them with others with different blooming cycles so my garden is always in full flower right through the growing season. However, you simply can’t beat a plant that blooms for 2, 3 or 4 months or more to help give your garden a solid base of continuous color. But there aren’t many plants out there that really bloom from spring through fall. 

A Daphne × transatlantica shrub covered in white flowers.
Daphne × transatlantica (here the cultivar ‘Blafra’ Eternal Fragrance) is the longest blooming shrub I know, but white corydalis still beats it hands down. Photo: WBLA_Corky. Flickr

Of course, there are annuals, most of which have an incredibly long blooming period, but they’re not in bloom in the spring and, worse yet, you have to replace them yearly. I still do plant many kinds of annuals, but I prefer more permanent plants. There are no everblooming bulbs or trees (at least not for cold climates) and precious few shrubs, although Daphne × transatlantica comes awfully close (read more about this fantastic shrub in the article The Shrub That Just Won’t Stop Blooming), but it isn’t solidly hardy in my USDA zone 3/AgCan zone 4b garden. Plus, under ideal conditions, white corydalis blooms for an even longer time.

Among blooming plants, therefore, that leaves perennials.

Geranium  Rozanne blooms all summer and into fall with purple flowers.
Geranium ‘Gerwat’ Rozanne™is awfully long-blooming, but not as long-blooming as white corydalis. Photo:

Now, if you ask most gardeners about everblooming perennials, they’ll mention gaillardias, coreopsis, a few geraniums (Geranium ‘Gerwat’ Rozanne™ is pretty incredible), some daylilies and maybe mauves and nepetas. All are great summer bloomers that continue well into fall, but … where is their spring bloom? Absent. One of the rare long-blooming spring-flowering perennials is Helleborus, but although it starts early enough, it’s all bloomed out by late June or early July. In fact, I’ve only found one family of plants that includes perennials blooming spring through fall, the Fumariaceae or bleeding-heart family. 

Dicentra ‘Luxuriant’ with blue green cut leaves and abundant pink flowers.
Some of the bleeding hearts, like this Dicentra ‘Luxuriant, are heavy spring bloomers, but peter out during the summer months, especially in hotter climates. Photo:

Better clones of the western bleeding heart (Dicentra formosa) and the fringed bleeding heart (D. eximia), plus hybrids between the two species (D. ‘Luxuriant’, D. ‘Adrian Bloom’, D. ‘Aurora’, etc.), are remarkably long-blooming, blooming massively in late May/early June then sporadically right through summer and early fall, at least in areas with cool summers, but you can’t trust them for summer bloom in hotter, drier climates.

 yellow corydalis with deeply cut blue-green leaves and yellow flowers.
Perhaps the second-longest blooming perennial is yellow corydalis (Pseudofumaria lutea). Photo:

Better yet is the yellow corydalis, Pseudofumaria lutea, formerly Corydalis lutea. It starts blooming a few weeks earlier than its relatives, the bleeding hearts, and continues just as long, into October. But even it is beaten by an even closer relative, white corydalis. 

And the Winner Is…

The finely cut leaves and the many flowers cive white corydalis extra elegance.
White corydalis (Pseudofumaria alba) will bloom pretty much all the time in a cool, yet snow-free climate. Photo: Andrea Moro, Wikimedia Commons

White corydalis or pale corydalis (Pseudofumaria alba, formerly Corydalis ochroleuca and Fumaria alba) is up and blooming by early May in my climate (it starts as early as February in its native southern Europe!), flowering along with the mid-season daffodils and tulips, and sails through the summer into October without stopping. November can be an iffy month where I live, with freezing nights and the first snows, but it keeps blooming right through them: the blooms don’t even seem to be damaged after a day or two under 10 cm of snow! What does stop it is when either the ground freezes solid or a long-lasting snow, one that will last until spring, settles in. Lasting snow usually arrives in mid to late November in my climate, but there are years when it comes late and the plant is still blooming in December. I’ve been told that it will bloom 12 months a year in climates where winters never include more than moderate frosts. Now that’s a long-blooming plant!

Keep It Cool

That said, white corydalis is not a good choice for climates where summer heat is a problem. Originally from mountain forest in southeastern Europe, it likes things reasonably cool at all times. It’s much hardier than usually claimed (I keep seeing USDA hardiness zone 5/AgCan zone 6 in references, yet it positively thrives in USDA zone 3/AgCan zone 4). It’s less likely to do well in the upper zones, beyond zone 8, where summers are torrid. Dry heat can even push it into summer dormancy.

The leaves are semi-persistant. They hang on into winter in my very cold climate, but are gone by spring, melting back to basically nothing. In milder climates, though, the leaves are present all year long.

Pretty as a Penny

Close-up of white cordyalis flowers.
Although the flowers appear creamy white from afar, up close, they’re white and yellow with distinct green markings. Photo:

Long-blooming and attractive too. Not a showstopper (the flowers are too small and their clusters too thinly spread for that), but pretty at all times. The blooms are borne densely on short spikes raised just above the foliage and appear creamy white from a distance. Up close you can see their unusual shape: generally tubular, but opening into lips with some yellow peaking out at the tip, while there is a green spot on the outside and a rounded white spur at the back. As one spike fades, others take its place and this continues until the ground freezes solid or the snow settles in.

Deeply cut foliage of white corydalis
The foliage is deeply cut and very attractive. Photo: Ewen Cameron, Wikimedia Commons

The foliage is attractive too: finely cut, fernlike and gray-green, perfectly setting off the flowers.

The plant is small to moderate in size, about 15 to 45 cm in height and about the same width. 

Good Care Means No Care

And did I mention it is easy to grow? Sun or shade seems to work equally well, as long as the plant gets some spring sun, and any soil will do as long as it is well drained, even alkaline soils. It positively thrives in dry shade where so few plants do well. I’ve been told it can go summer dormant in hot, dry climates when planted in full sun: if that describes your summer conditions, plant it in shade. Elsewhere full sun is fine. It requires no pruning, deadheading, staking nor any other meticulous care, nor does it seem to have any insect or disease problems and deer, rabbits and other mammals pay no attention to it. Just plant it and let it do its thing … which includes self-sowing.

Naturalized white corydalis mixing in with other plants, white flowers.
White corydalis self-sows modestly, naturalizing in open spaces in your landscape. Photo:

Yes, it does get around. It’s not one of those invasive plants that crushes its neighbors, but rather pops up here and there, filling in open spaces. If you like formal plantings where every plant remains in its designated spot, simply don’t plant white corydalis: it is just not that kind of plant. It is, however, a plant you’ll adore if you like English-style mixed beds or naturalized woodland gardens.

White corydalis loves to sow itself into rock walls.
White corydalis seems to love rocks and will self-sow into the slightest crack of a rock wall. Photo:

It also likes rocks and has sown itself into a few retaining walls at my place. And thank goodness for that! Planting in rock walls is such a pain that I love plants that do it on their own.

And you do want the plant to self-sow, as it is not long-lived. I’ve been told that individual plants rarely live more than 2 or 3 years … but I’ve never had to notice, as there are always enough replacements in about the same spots that the death of a specimen or two doesn’t show. And it can only be propagated by seeds … fresh seeds. The best way to share plants with a friend is therefore to pot up any stray babies. 

Now the real downside: white corydalis is hard to find in nurseries. But do ask. You’ll be surprised at how many have it in their display gardens but have never bothered to pot it up. Or try ordering seeds by mail. Jelitto Perennial Seeds is one company that carries it.

So there you go: simply the bloomingest perennial ever and so easy to grow. Try it and see!

How Does Biochar Work to Improve, or Even Decontaminate, Soil?

Biochar made from fruitwood chips.

Fruitwood pyrolized into biochar. Photo: Jeff Novak, USDA-ARS.

An article by Jim Ippolito, Colorado State University

Biochar – as the name implies – is made from formerly living substances. Source materials can be plant materials like leaves, stems and woody tissue. Biochar can also be made from manure or even biosolids (the solids left after wastewater treatment). Biochar is the material left over after burning one (or more) of the items above in a low- or no-oxygen environment.

The finished material itself can look like charcoal or ashes left over after a campfire. Biochar can be made in several different types of furnaces. The source material as well as the temperature at which biochar is made makes a difference in how the biochar functions.

When biochar is made at relatively low temperatures, some organic materials remain in the biochar. Some of the organic matter is still usable for plants and soil microbes to use as nutrient sources. In this way, applying biochar improves soil nutrients, and can help plants grow better. Adding biochar to soil can improve its texture, too, allowing for more water filtration during rainstorms and snowmelt.

Bowl of fruitwood chips being put into a pyrolyzer.
Fruitwood chips before firing into biochar through a process called pyrolizing. Photo: Jeff Novak, USDA-ARS.

In addition, the organic materials of biochar can form associations with chemicals in soils. Lower temperature biochars contain “functional groups.” These chemical portions of the biochar molecules can trap other chemicals in soils. Functional groups can trap both organic chemical contaminants – like pharmaceutical waste – and heavy metals. This protects plant life from the harmful effects of these chemicals.

You may not know that soil typically has a negative charge – depending on how much clay the soil contains. (For a review on how soil has a charge, visit this Soils Matter blog:  Soil: Largest Reactor on the Planet?). Similarly, biochar is often negatively charged, and when added to soil, this can enhance and chemically attract positively charged chemicals. Biochar made at a low temperature has a structure that can hold, but not change, the toxic metals. This reduces the amount of heavy metals that can get inside plants.

Another feature of biochar is its high surface area. Think of it like a charcoal sponge. This large surface area can hold a lot of chemicals and toxic metals, making it quite valuable.

When biochar is made at relatively high temperatures, most functional groups are lost. This type of biochar can still improve and decontaminate soil, but in different ways. What remains are mostly carbon ash and some helpful chemicals such as carbonates, oxides and hydroxides. These materials can chemically react with heavy metals in soil. This changes the metals into forms that are less soluble and therefore less available to plants. Addition of high-temperature biochar helps reduce metal toxicity and allows plants to grow in areas where they typically couldn’t thrive.

Scientists are researching uses of biochar to help reclaim heavy metal contaminated soils in former mining sites. Plants have difficulty growing in soils found near some historic mining areas due to excessive soil metals. Additions of biochar have successfully improved soils so plants can grow.

So, how do biochars work to improve or decontaminate soil? Adding biochar to soil can add organic nutrients that plants and soil microbes need as food source. It improves the physical structure of soil, improving water movement. And materials and compounds in biochar can even help contaminated soils by holding onto or chemically reacting with heavy metals and other soil contaminants.

This blog was adapted from an article appearing on the Soil Science Society of America (SSSA) website, a progressive, international scientific society that fosters the transfer of knowledge and practices to sustain global soils. Its members are dedicated to advancing the field of soil science. It provides information about soils in relation to crop production, environmental quality, ecosystem sustainability, bioremediation, waste management, recycling, and wise land use.

Starting a Witch-Hazel Off on the Right Foot

American witch-hazel in bloom in fall, yellow flowers.

American witch-hazel is one of the few witch-hazels that blooms in the fall rather than the spring. Photo:

Question: My landscaper planted an American witch-hazel at the end of a major relandscaping project in my garden last July. Since I had to water the new lawn every other day, it received a lot of water and I think the shrub got a bit overwatered, because it didn’t survive. However, my landscaper agreed to replace it with a new one this spring.

Do you have any specific advice for making sure this new witch-hazel survives? Fertilizer, watering, planting advice, type of soil, etc.? I just love this shrub with its late flowers and bewitching scent and want to make sure I succeed this time!

Sophie Blanchet

Answer: I think you’re right about the overwatering, as American witch-hazel is not considered in any way difficult to grow. But it’s hard to meet the considerable water requirements of a freshly installed lawn without harming the surrounding plants at least a little, and freshly installed plants are just a bit more fragile than others. So, essentially, you were unlucky … but, with the lawn now well established, there’s no reason to be very concerned about this spring’s planting.

Spring foliage of American witch-hazel
Witch-hazel leaves in earliest spring. Photo:

The American witch-hazel (Hamamelis virginiana) is not very particular about its needs. Just water it normally, that is, soak the root area when the soil feels dry to the touch, then wait until the soil is to dry out again before watering again. That way, it should settle in perfectly. By the second year, it should need practically no care whatsoever, except watering during periods of extreme drought.

In nature, American witch-hazel grows over a wide climatic range, throughout much of temperate Eastern North America. Ill.:

Witch hazel adapts just about every soil type: rich to poor, moist to relatively dry, and acidic to neutral. However, it won’t tolerate saline soils nor very compacted ones. It’s even adapted to both sun and shade: how many other shrubs are that versatile? In the wild, it grows from southern Canada to northern Florida, so shows a considerable hardiness range: USDA zones 3 to 8; AgCan zones 4b to 8, although it is a temperate climate plant and won’t do well in areas with very mild winters.

There is nothing special to emphasize about planting a witch-hazel compared to any other shrub. Just prepare a hole the same depth as the root ball and three times as wide, center the plant inside and backfill the hole with the soil you removed. Amending the soil is not recommended. Gently tamp the soil down and water thoroughly. Cover the areas with 2 to 4 inches (5 to 10 cm) of the mulch of your choice in order to moderate soil temperatures and reduce evaporation. It will need little if any fertilizer: as the mulch breaks down, it will supply any minerals necessary. Just top the mulch up as necessary (some mulches decompose more quickly than others).

A large shrub of American witch-hazel with yellow flowers near a retaining wall and brick path.
American witch-hazel is a very large shrub and might need a bit of pruning if you plant it on a small lot. Photo:

Finally, American witch-hazel being a very large shrub, even a small tree, from 11 to 20 feet (3.5 to 6 m high and wide), you might find it necessary to prune it from time to time to keep it under control. This is best done in late fall after flowering.

Best of luck this time around!

Cage Your Climbing Roses


Climbing roses are much less work if you cage them. This is Rosa ‘Graham Thomas’. Photo:

Traditionally, climbing roses are fixed to a wall, trellis, arbor, pergola or other structure. That’s because despite the name “climbing rose,” they really don’t climb unaided. Unlike true climbing plants, they have no tendrils, twining stems or clinging aerial roots they can grasp onto the structure with. You have to take their long, fairly rigid canes and force them to bend toward their support, then tie them to it, manually, with twine, clips or ties. And all that using the greatest care, at that, as those canes are very thorny. 

Helpful Hint: When working with roses, always wear thick, long-sleeve rose gloves.

Man attaching a climbing rose to a trellis.
Traditionally roses are attached by hand to the outside of their support. Photo: Heirloom Roses
Climbing rose growing up inside an obelisk
When a climbing rose is planted inside a cage or obelisk, it can lean on one side or the other of the structure over its entire height and won’t need you to tie it into place. Photo:

But as the season progresses, and at the risk of getting seriously scratched once more, you need to go back again and again and tie any branches that have grown free back to the support. It almost feels like the rose is purposely to sending its branches in all the wrong directions, nowhere near its support, just to annoy you!

Generations of gardeners have done just that. But does it really make sense to keep attaching these plants to the outside of their support over and over all summer? At least, when there is an easier way?

The secret to easy climbing rose support is to grow it not outside its support where it will need to be tied into place, but inside a hollow support it can lean on, yet not escape. So it can grow mostly on its own. A structure that could be a cage, a column, a tower or an obelisk. And it turns out it’s so easy to do!

For example, you could build a basic cage just by fixing three or four sections of sturdy trellising together or simply buy one of those garden obelisks that are so popular these days. You’ll need a fairly tall one, at least 6 feet (1.8 m) high. 8 feet (2.5 m) would be even better if your favorite climbing rose is a tall one. You need considerable height to create a good pillar effect.

If you search a bit, it’s possible to find some truly sturdy tomato cages—sometimes called tomato towers—that would be perfect for a climbing rose. Photo:

Or use a tomato cage and simply grow a rose bush inside it. Of course, not one of those everyday, flimsy, wire tomato cages that can barely support the weight of a tomato plant let along a rose and which, besides, aren’t even close to being tall enough, but a good, sturdy, extra-tall tomato tower. There are some great models available in all sorts of shapes, materials, colors and sizes. 

Or you can build your own “rose pillar.” In fact, it’s a just a basic tomato cage, the very model I use for my own tomato plants, but if you tell visitors it’s a rose pillar and plant a climbing rose inside it, I guarantee they’ll believe you.

A Tomato Cage-cum-Rose Pillar

A roll of concrete mesh cut into 6 foot lengths will make great tomato cages… I mean, rose pillars! Photo:

To make your own rose pillar, you need concrete mesh, also called concrete reinforcing wire. It’s used to make reinforced concrete and should be available in any hardware or building supplies store. You can find it with either 4- or 6-inch (10- or 15-cm) openings (both work fine) and in widths of 4 to 6 feet (120 to 180 cm). In fact, even greater widths are also available, but harder to locate. 6 ft/180 cm is sufficient for a rose pillar for a moderately robust climbing rose. If it’s rusty appearance bothers you, you can splurge and buy galvanized concrete reinforcing wire.

Cut the concrete mesh with wire cutters into sheets 6 feet (180 cm) wide. Wear rose gloves for this as well: cut wire can make nasty gashes! Better yet, have the clerk at the hardware store cut it for you. 

Concrete reinforcing wire rolled into a tube.
Roll the concrete reinforcing wire into a cut and hook the cut ends over to hold them in place. Ill.: Claire Tourigny

Once home, roll each sheet into a column, bending the metal ends into hooks to hold the column together.

Now just place the cage over a young climbing rose and fix it solidly to the ground with tent stakes or some other kind of staking method so it remains upright … then just let your rose grow! All you have to do, as mentioned above, is to push any wayward stems back into the confines of the cage during the early stages.

The Right Rose for Your Climate 

You now need to pick the right rose. 

John Cabot rose with double pink flowers.
The ‘John Cabot’ rose is perhaps the hardiest of the climbing roses. Photo: Doug Waylett, Flickr

In most colder climates, the grandifloras and hybrid teas often used in rose pillars in public gardens are cut back by the cold each winter and will simply never reach the height you need. Look instead for a climbing rose, ideally one that is fully hardy in your area. That way, you won’t have to deal with winter protection.

In cold regions, such as hardiness zones 3 and 4, the “climbing” roses from the Explorers series, ‘John Cabot’, ‘William Baffin’ or ‘Henry Kelsey’, or ‘Félix Leclerc’ from the Canadian Artists series, are good choices. They aren’t really pure climbing roses, but rather shrub roses with climbing tendencies.

Climbing rose ‘White New Dawn’ with white flowers
Climbing rose ‘White New Dawn’. Salycina, Wikimedia Commons

In zones 5 and 6, there are a few fairly hardy true climbing roses you could use, like ‘New Dawn’, ‘Zéphrine Drouin’, ‘Blaze Improved’, and ‘White New Dawn’. Some of the English roses, like ‘Gertrude Jekyll’, ‘Graham Thomas’, ‘Constance Spry’, ‘The Generous Gardener’, ‘Strawberry Hill’ and ‘Tess of the d’Urbervilles’, make good pillar roses too and should be hardy in zone 5. If not, certainly in zone 6.

Climbing rose with pale orange flowers
The milder the climate, the easier it is to find climbing roses that will be easy to grow. Photo: Paul Zimmerman Roses

And if you live in an even milder hardiness zone, 7 to 9, well, the sky really is the limit, isn’t it? There are hundreds of climbing roses you can grow, some actually far too tall for a 6-foot (180-cm) rose cage. (Some of those rambling roses can easily reach 20 feet/6 m in height!) Ask a local rosarian for few varieties of modest height that do really well in your climate.

Basic Care

Plant your climbing rose in full sun or nearly full sun in good, well-drained garden soil and place the cage or obelisk over it as mentioned above. 

An ‘American Pillar’ rose at the “arching rose pillar” stage. Photo: Petals from the Past

Early in the season, you’ll need to push any wayward canes that wander out of the structure back inside, but the rose usually switches to a convenient upward growth habit and won’t need much encouragement. Once it reaches the top, just let it grow pretty much on its own, removing only stems that get in your way (who wants to be snagged by a thorny rose cane as they stroll by?).

With such minimal pruning, you’ll end up with a what I call an “arching rose pillar”: a pillar coiffed with an arching dome of composed of those canes that reached the top and are now stretching out in all directions: a real firework of flowers! 

And because you used roses adapted to your climate, you’ll only need to offer minimal care … well, minimal care for roses, that is: watering during periods of drought, fertilizing, suppression of dead or damaged canes, insect and disease control, etc.

So, what do you think? Wouldn’t a rose pillar make a rather neat little garden project for the coming summer? All you need is sun, a tough, no-nonsense climbing rose and a robust cage or obelisk. So simple!

Adapted from an article originally published in this blog on May 28, 2015

Year of the Garden Bean

Illustration of green beans and leaves, with 2021 year of the garden bean overprint

Every year, the National Garden Bureau, a non-profit organization promoting the pleasures of home gardening, selects one annual, one perennial, one vegetable, one shrub and one bulb to celebrate. It’s a great way to discover a new plant or to learn a bit more about a plant you may already be growing.

Let’s look at the vegetable chosen for 2021, the garden bean.

There are many species of beans in cultivation around the world, yet it is the common garden bean, Phaseolus vulgaris, that takes on celebrity status as National Garden Bureau’s vegetable focus for 2021.

Illustration showing three sisters culture: beans, corn, squash.
Beans are one of the three sisters of vegetables grown by the native peoples of the New World. Ill.: Anna Juchnowicz, Wikimedia Commons

One of the earliest cultivated plants, garden beans were domesticated somewhere in central Mexico around 6,000 BCE, then spread both north and south, into South America, as an original member of the original “Three-Sisters”—an interplanting of three domesticated crops: maize, winter squash and climbing beans. These became the three main agricultural crops used for trade and food for Native North Americans.

Map showing how beans traveled around the world.
How the bean traveled from its Mesoamerican homeland to the entire world over the centuries. Ill.: &

Christopher Columbus was among the first Europeans to have seen the garden bean. He brought it back to Europe from his second voyage to the New World in 1493. The New World legume was immediately confused with the broad bean (Vicia faba), an Old World legume, and thus given the name common “bean”, although the two plants are actually very distant relatives. 

The new bean (P. vulgaris) caught on quickly. By the 17th century, it was already cultivated throughout Italy, Greece and Turkey and reaching Africa and Asia. Today, it is grown all over the world.

Green beans were once referred to as string beans due to the long fibrous thread along the pod seams. The first stringless green bean was developed in 1894 by Calvin Keeney who later became known as the “Father of the stringless bean”. Breeders continue to breed this stringless trait into modern genetics. Other desirable traits include dark green succulent pods, good bean flavor, concentrated fruit set, stress tolerance, and disease resistance.


yellow, green and purple beans in a basket.
Garden beans come in a variety of colors in including yellow, green, purple and mottled. This is Mardi Gras Blend of bush beans. Photo:

The garden bean is a highly variable species. Originally a climbing species grasping through twining stems and reaching up to 10 feet (3 m) in height, many modern cultivars are determinate, bush-forming types, no more the 8–20 inches (20–60 cm) tall. All varieties bear alternate, green leaves divided into 3 oval leaflets. Flowers are white, pink or purple and about 1 cm in diameter. They largely self-pollinate prior to opening, but not all ovules are fertilized before the flower does open, so that allows some cross-pollination to occur from insect visits. The flowers give way to pods 3–8 in (8–20 cm) long of variable width. The green, yellow, black or purple pods each contain 4–8 smooth, kidney-shaped beans that range widely in color and are often mottled.

Basic Types of Garden Beans:

Pole bean climbing on a trellis
Pole beans can be grown on arbors, trellises and teepees. They take up a bit more garden space than bush bean, but offer harvests over a much longer period, giving the home gardener more bang for their buck. Photo:

The common garden bean is anything but common! Green beans or “snap” beans as they are also called come in a variety of flavors, pod shapes and sizes as well as a colorful palette of colors.

  • Bush beans are the workhorse of the garden and the mainstay in the kitchen. Bush beans are compact and fit well into both small garden patches or patio containers. They are determinate, flowering early at the ends of the stem.
  • Pole beans with their vining habits can be trained up poles, trellises, netting, or supportive structures such as a teepee. With proper support, pole beans can also be grown in containers. Indeterminate and a bit slower to produce than bush beans, they grow at the tip and produce flowers and seeds from the leaf axils.
  • Wax beans are simply beans with yellow pods. They can be bush beans or pole beans.
  • Filet beans or haricots verts (French green beans) are distinguished by elegant ultra-slim pods. Due to their delicate appearance, filet beans are gaining in popularity with foodies and chefs. Filet beans come in both bush and pole bean types.
All different colors of dried beans.
Dried beans come in a multitude of colors. Photo:
  • Dried or shelling beans are grown for their edible seeds rather than edible pods. Pinto beans, kidney beans and black beans fall into this category.

Varieties to Try:

Pole Beans

Harvested ‘Kentucky Blue’ pole beans, with long green pods.
Although launched only in 1991, ‘Kentucky Blue’ pole bean is already an old favorite. Photo:

Bush Beans

Mascotte bean in flower box showing fruit borne above the foliage.
‘Mascotte’ holds its pods above the leave, making for any easier harvest. Photo:
  • Mascotte’ — A gourmet compact variety perfect for today’s small space gardens. Produces long slender pods that stay above the foliage for easy harvest. 2014 AAS Winner.
  • Desperado’—Heat and stress tolerance makes this an easy to grow and high yielder of long straight 5″ (12 cm) dark green pods.

Specialty Beans

Flat podded green beans in a hand.
‘Roma II’ is a typical Romano bean with long, flat pods. Photo
  • ‘Roma II’ — A romano or Italian flat bean that produces an abundance of wide, flat 5″ (12 cm) long pods with a distinctive rich, intense, beany flavor. Bush type habit.
  • ‘Amethyst Purple’ — A French filet bush bean that produces beautiful violet-purple, long slender stringless pods on compact plants suitable for containers and raised beds.
Bright yellow wax beans.
‘Gold Rush’ is perhaps the classic wax bean. Photo:
  • ‘Gold Rush’ — The gold standard for yellow wax beans, ‘Gold Rush’ produces clusters of straight 5–6″ (12–15 cm) long yellow pods. Pods hold well on the bush and are versatile in the kitchen.

Garden Beans Growing Tips:

  • Beans are warm-weather vegetables and are best planted after soil temperatures reach 70˚F (21˚C).
  • Avoid sowing too early in the season. Cool, wet soils can lead to rot.
  • Beans thrive with at least eight hours of daily sun, moderate fertility, and well-drained soil.
Rhizobial inoculant for beans only needs to be applied once. Photo: Home Hardware

Helpful Hint: For best growth and productivity, add rhizobial inoculant to the garden soil the first time you grow beans. This product, made up of beneficial bacteria, can be found in garden centers, feed stores and online. It forms small nodules on the plant’s roots that take nitrogen from the atmosphere, unavailable to most other plants, and convert it into a form that bean plants can use for their growth. Once in the garden, rhizobia can survive for years on any green matter mixed into the soil, even if no beans are grown, so only the initial treatment is needed.

  • Beans have shallow roots: weed carefully to prevent damage to the root system.
  • Mulch the soil around the bean plant; consistent moisture results in the highest quality harvests.
  • Quick to mature, harvests can begin 50–60 days after sowing.
  • Bush beans typically grow 12 to 24 inches (30–60 cm) tall and produce harvests for about 3 weeks.
  • Succession sowing of bush beans every 2–3 weeks will produce delicious beans all season.
  • Pole beans have a long harvest season, generally lasting about 6 to 8 weeks.
  • Harvest frequently to encourage pod production. If you let even one pod mature on the vine, this will stop the plant from producing new ones.
  • Pole beans can quickly grow a lush privacy wall around porches or patios.
Teepee of beans with two children playing inside.
You can create a living teepee for your children’s pleasure. Photo:
  • Create a living fort or teepee with pole beans for a fun play space.
  • Wax beans’ golden color is due to their lack of chlorophyll. They retain their beautiful golden color when cooked.
  • Purple beans contain anthocyanins (the purple pigment) that disappear when beans are cooked.
  • Bean seeds are easy to store for 3 to 5 years. Just seal your excess seeds in their original pack with a piece of tape and keep them dry and at room temperature or cooler until you need them.

Garden Beans Harvesting Tips:

Hand holding yellow bowl of green beans.
Beans (here, ‘Bush Blue Lake’) are ready to harvest when they snap. Photo:

A good indication of when to harvest is to reference the days to maturity indicated on the seed pack of the specific variety. Pick green beans when pods are young and tender, just before the seeds begin to swell. Beans will “snap” when you bend and break them. If they are immature, they won’t snap!

Fresh unwashed green beans should remain fresh for up to a week when stored in a reusable container or plastic bag in the refrigerator.

Versatile in culinary preparation, garden beans can be eaten raw, steamed, boiled, stir-fried, grilled or baked. For the best eating experience, cooked green beans should still have a crisp texture and an appetizing bright green color.

Bean leaves and flowers are also edible. Simply add them to any vegetable dish for extra nutrition and flavor.

Green beans pair well with a variety of herbs, spices, and flavors. Parsley, rosemary, sage, savory, thyme, a splash of lemon juice or a pat of butter are very popular additions to bean dishes. You can’t go wrong with the simple addition of garlic and onions. There are some who swear green beans cry out for bacon bits or a dollop of bacon grease added to the cooking pot.

Green beans are bred for eating fresh or processing/preserving. Some varieties are well suited for both. Processing beans, such as ‘Goldmine’, ‘Blue Lake’, ‘Tendercrop’ et ‘Kentucky Wonder’, are better able to retain their beautiful color and texture for canning, pickling, and freezing. If you look forward to gifting out jars of pickled green beans, a processing green bean will yield you the best results.

What About the—um, uh—Gas?
Yes, beans can have a minor side effect. Photo:

Well, yes, that!

Beans do cause a problem with flatulence, although the degree varies from one individual to another. Beans contain special sugars called oligosaccharides (particularly raffinose and stachyose) which our bodies can’t digest. They make it intact through our small intestine, then bacteria our large intestine finally break them down, causing fermentation and the production of sulfur-rich gas we release as flatulence. 

The good news is that there is an enzyme called alpha-galactosidase, derived from the fungus Aspergillus niger, that, if ingested with beans, will prevent the smelly fermentation. So, take an enzyme pill (Beano is the best-known brand) before you eat and chow down on beans to your heart’s content!

Are Garden Beans Poisonous?

Red kidney beans in a bowl with a spoon and superimposed "toxic" symbol.
Kidney beans can be toxic is not carefully prepared. Photo:

Garden beans contain a toxic compound called phytohaemagglutinin which, although not fatal, can cause severe gastric distress. It is found in small quantities and therefore harmlessly in green and wax beans, as well as in leaves and flowers, but can be found in toxic levels in red kidney beans and, to a lesser extent, white ones. As few as five raw kidney beans can cause problems. The compound is largely destroyed by soaking and cooking, so boiling fresh kidney beans in the pod for 30 minutes before eating is recommended. Dry beans need to be presoaked for 5 hours (the water should then be discarded) before boiling for 30 minutes. Outbreaks of poisoning have been associated with cooking kidney beans in slow cookers, as they don’t heat beans to the boiling point and therefore don’t destroy the toxin.

What Is a Bean?

Broad beans and flowers of broad bean.
The broad bean, or fava bean (Vicia fava), is the true bean gave all other beans their name. Photo:

The garden bean (Phaseolus vulgaris) is not the only plant with the name bean. In fact, it isn’t even the first one to bear that name. The title place belongs to the broad or fava bean (Vicia fava). 

Other beans, all in the Fabaceae family, include:

Yardlong beans on the vine.
The yardlong or asparagus bean (Vigna unguiculata sesquipedalis), like ‘Orient Wonder’, can have pods up to 43 inches (110 cm) long, but is only a distant relative of the garden bean. Photo:
  • Adsuki bean (Vigna angularis)
  • Garbanzo bean or chickpea (Cicer arietinum)
  • Hyacinth bean (Lablab purpureus)
  • Lima bean (Phaseolus lunatus)
  • Mung bean (Vigna radiata)
  • Scarlet runner bean (Phaseolus coccineus)
  • Soybean (Glycine max)
  • Tepary bean (Phaseolus acutifolius)
  • Winged bean (Psophocarpus tetragonolobus)
  • Yardlong or asparagus bean (Vigna unguiculata sesquipedalis)

And there you have it: the wonderful, productive, delicious garden bean. Where would the world be without it?

This article was based on the Year of the Garden Bean fact sheet from the National Garden Bureau. 

Interested in buying garden beans to grow for yourself? Click the here to shop members of the National Garden Bureau.

Urban agroforestry and its potential integration into city planning efforts

Fruit trees for urban forestry: Kousa dogwood, jujube, American persimmon, pawpaw.

Urban agroforestry makes efficient, double use of space. Trees that produce food can line city streets, parks, and other spaces. Right, from top: Kousa dogwood (Cornus kousa), jujube (Ziziphus jujuba), American persimmon (Diospyros virginiana), pawpaw (Asimina triloba). Credit: Sarah Lovell.

An article by Dr. Sarah Lovell, University of Missouri-Columbia

Should we reimagine a “garden city” that could help adapt our urban areas for a variable and uncertain future? One that provides several benefits, like cooling the city, providing green areas for city dwellers, and even a fresh food supply?

That type of question is studied by scientists in the field of urban agroforestry. As you can imagine, plant science, horticulture, agriculture, forestry, and other sciences contribute to the development of urban agroforestry. These scientists work with landscape designers and urban planners to purposefully integrate food production into the fabric of the city. But there are some hurdles that need to be overcome to get to our garden city of the future.

One barrier is that the value of land in cities is high. There is usually limited space, and the space available is expensive. In addition, zoning and tax policies may prohibit or restrict food production. Land in cities can also be contaminated. This could be from former industrial plants, lead paints from residential structures, or other contaminants.

Defining Urban Agroforestry

It is possible to provide tree or shrub canopies that also produce food, but getting to that goal could be complicated. Fruits, nuts, and berries are just a few examples that could be provided by the right plant material. This type of system is not meant to replace the current food system, but to complement it.

Woody species of trees and shrubs are perennial, not needing to be replanted each year. They can be described as “permaculture”—or permanent agriculture. You may have a patch of your own gooseberries or plums you enjoy from your garden. The concept is the same, but on a bigger scale.

Urban Agroforestry Can Advance Urban Food Production

Urban agroforestry could serve as a progressive form of urban agriculture. The woody species would need to be integrated into an overall plan, to consider multifunctional uses for the community. People tend to prefer the aesthetics of landscapes that include trees, and fruiting trees that could be incorporated into city parks or other public spaces.

Trees and shrubs are also less affected by certain soil contaminants. The fruits and nuts usually don’t touch the ground—assuming they are harvested before they fall! Research has shown that root crops and leafy vegetables are more at risk of being contaminated with lead or arsenic than above-ground crops like tomatoes.

Juneberries, also called serviceberries and saskatoons (Amelanchier spp.), can be grown in cities. Their flavor is similar to a blueberry but with a hint of almond, and they can grow in a wider range of soil types.

Urban agroforestry can contribute to human health, because some of the most nutrient-dense foods can be grown in these systems. Berries like blueberry, aronia, and elderberry contain very high levels of antioxidants, and they grow on shrubs that are native and adapted to many parts of the US and Canada. Trees can provide healthy black walnuts, pecans, or nuts and fruits to diversify and improve the human diet.

Other Benefits of Urban Agroforestry

Perennial trees and shrubs grown as part of an urban agroforestry program also provide other benefits. Besides offering shade in the space beneath the trees, they can also shade buildings. Their roots can help stabilize the soil, preventing erosion. They contribute to the water cycle, absorbing water from extreme weather events and returning it to the air through their transpiration. Another benefit is that these types of food sources don’t need the regular fertilization and maintenance that typical agricultural crops need.

Using and Repurposing Urban Sites

Cities often have abandoned or underused sites. Abandoned lots, sidewalk medians and other spaces could have perennial, food-producing trees and shrubs. Other spaces, like pre-existing parks and even cemeteries, could be included in planning for urban food systems.

Garden Cities Are Urban Agroforestry

Planting more trees is considered to be on one of the most effective strategies for adapting to and reducing the effects of climate change. Why not have those trees (and shrubs) also provide the benefit of producing food for residents? These multi-purpose garden cities are the goal of urban agroforestry!

This blog is from the Sustainable, Secure Food Blog, subtitled Growing Food for All, Sustainable for our Earth, and was adapted from an editorial by Dr. Lovell in Urban Agriculture and Regional Food Production
All photos by Sarah Lovell

This blog was sponsored and written by a member of the American Society of Agronomy and Crop Science Society of America. Their members are researchers and trained, certified, professionals in the areas of growing our world’s food supply while protecting our environment. They work at universities, government research facilities, and private businesses across the United States and the world.

15 Fun Facts About Orchids

Plusieurs phalaenopsis of different colors.

Phalaenopsis or moth orchids are currently the most popular orchids. Photo:

So many of us grow orchids, but what do we really know about them? Here are some fun facts about this fascinating group of plants.

Illustration of multiple different orchids.
Illustration of orchid diversity from Kunstformen de Nature, by Ernst Haeckel (1899)
  1. The orchid family (Orchidaceae) is, with the Asteraceae* or sunflower family, the largest in the world, containing some 28,000 species distributed in 763 genera. There are four times more orchid species on this planet than mammal species!

*Which family is actually larger is debatable, because data on different species is always changing.

  1. Orchids are both very ancient and very modern. They are among the oldest known flowering plants, with the oldest dating back 112 million years ago to the Early Cretaceous, when dinosaurs ruled the earth. By 64 million years ago, they had evolved pollinia and by 35 million years ago, many had become epiphytes. However, orchids continue to evolve to this day and about 20 new species are described every year. 
Map showing world distribution of orchids.
Orchids are found all over the world. Ill.: Dalton Holland Baptista, Wikimedia Commons
  1. Orchids are not just tropical, as you might expect, given the current popularity of houseplant orchids, but are found all over the world, from the equator to the Arctic Circle. And in most environments, too, from arid climates to tropical jungles. They are found on every continent except Antarctica.
  2. Orchid flowers have variable durations. Some last only hours (Sobralia spp, for example, last barely a day) while others last months (many Phalaenopsis hybrids). Probably the average lifespan of an orchid flower is about 2 to 4 weeks.
The world’s largest orchid with a man standing nearby.
The world’s largest orchid: the giant orchid (Grammatophyllum speciosum). Photo: Schuiteman,
  1. The world’s largest orchid, is the giant orchid or tiger orchid, Grammatophyllum speciosum, which can measure up to 7.62 m (25 ft) in height and weigh up to 2 tons, bearing thousands of abundantly spotted flowers at once. In spite of its size, it mostly grows as an epiphyte, high up in the branches of forest trees on the islands of Southeast Asia. 
The world’s smallest orchid with a finger to compare.
Platystele jungermannioides in full bloom isn’t much larger than a fingernail. Photo: Orchids Wiki
  1. The world’s smallest orchid is, officially, Platystele jungermannioides of the cloud forests of Mexico, Guatemala, Costa Rica and Panama. The plant itself about the size of a dime, including the leaves, roots and flowers. An even smaller orchid was recently discovered in Ecuador, but it has yet to be officially described.
Orchid seed pod split open.
Orchid seeds are no larger than dust. Photo: Blue Sky Channel,
  1. Orchids have the smallest seeds in the world, no larger than a speck of dust, with those of the New Caledonian species Anoectochilus imitans are said to be the smallest of all, measuring just 0.05 mm in length. A single seed capsule of some species can contain up to 4 million seeds. This is largely because orchid seeds, unlike other seeds, have no food reserve. To germinate, most first have to form in a mycorrhizal relationship with a fungus that will supply the nutrients they need in order to grow. 
Vanilla orchid with flowers and dried flowers.
The vanilla orchid is the only orchid grown commercially for its edible parts.
  1. Only one orchid among all the thousands of species is considered to have an edible fruit. The seed pods (beans) of vanilla orchids (Vanilla spp.) are harvested and produce the well-known vanilla flavoring. It is the second most expensive spice in the world after saffron.
Greenhouse full of phalaenopsis orchids.
Moth orchids (Phalaneopsis spp.) are the most widely grown orchid in the world. Photo:
  1. Moth orchids (Phalaneopsis species and hybrids) are currently the most widely grown houseplants in the world, now superceding the popular Christmas plant, the poinsettia (Euphorbia pulcherrima), with sales increasing annually. They are grown by the millions on all continents and, yes, even—indoors, of course—in Antarctica, where there are reports of one being grown in a research studio.
Paired tubers of a Orchis species.
The name orchid comes from the Ancient Greek word for testicle because of the paired tubers of the Orchis orchid. Photo:
  1. The name orchid comes from plants in the the genus Orchis, such as Orchis mascula, and derives from the Ancient Greek word orchis meaning “testicle”; because of the shape of the paired underground tubers of this terrestrial European species. The term “orchid”, which is just a shortened form of the family Orchidaceae, was not introduced until 1845.
Orchid flower showing petals, sepals, lip and column
  1. Orchid flowers are quite unusual. While they have the usual 6 tepals (3 petals and 3 sepals) common to most other monocots, one of the petals is highly modified. Called the labellum (or lip), it is typically quite different from the other tepals both in shape and color. It usually functions to attract insect pollinators and direct them to the flower’s column where it’s sexual organs are concentrated.
  2. The column in the center of the flower is fairly unique as well. It’s a fusion of the stamen, where the pollen is made, and stigma, where the pollen germinates. On most other flowers, these are separate parts, rather grouped into a single organ. 
Bee with pollinia stuck to its back.
Tropical bee with pollinia stuck to its back. Photo: Mindy Lighthipe-Artist
  1. The pollen of orchids is not exposed on the anther at the tip of stamen as in most flowers, but is condensed into a dense mass called a pollinium (plural pollinia). When an insect visits an orchid flower, the pollinia is typically glued to its body and the insect then carries it to the flower of another orchid of the same species where it becomes caught and is pulled free, thus fecundating the flower and leading to seed production.
Vanda orchids with thick roots.
Ephiphyic orchids (these are vandas) usually have thick roots covered in water-absorbing vela men. Photo:
  1. Orchid roots too can be pretty special, especially in the case of epiphytic orchids (the ones that grow on trees). They’re aerial and reach out in all directions, eventually fixing themselves to branches and bark in the wild. They’re very thick and covered with a spongy whitish to brownish epidermis called velamen whose role is to absorb and hold moisture. When moistened, these roots often show an underlying greenish coloration due to the presence of chlorophyll and carry out some photosynthesis. Indeed, some orchids have no leaves at all and carry out photosynthesis uniquely through their photosynthetic roots.
Illustration of sympodial and monopodial orchids.
Sympodial and monopodial: two ways of growing. Photo: My First Orchid
  1. Orchids are classified into two groups. Those that grow up from a single stem, such as Phalaneopsis and Vanda orchids, are said to be monopodial (mono = single / pod = foot). The majority, however, grow horizontally along a creeping, branching rhizome and are called sympodial (sym = many / pod = feet). This includes such genera as CattleyaCympdidium, Dendrobium and Oncidium. Many tropical sympodial orchids produce a line of bulblike structures at their base called pseudobulbs. Each pseudobulb blooms only once, but by then another or several other pseudobulbs will be forming and each will bloom in its turn. Leafless older pseudobulbs that have already bloomed are called back bulbs and serve as an energy and water reservoir for newer growth. Monopodial orchids are usually reproduced by stem cuttings, unless they produce an offset (keiki or baby orchid) that can be cut free and rooted. Sympodial orchids are mostly multiplied by division.

So there you go: orchids have been mass-produced to the extent they are now common, everyday houseplants … but that doesn’t mean they don’t have their fun little secrets!

Five Good Reasons to Grow Your Garden from Seed

Heirloom flowers such as sweet william (above), love-in-a-mist and love-lies-bleeding offer romance, drama, and fragrance to the garden, and they draw pollinators!

Heirloom flowers such as sweet William (above: Dianthus ‘Jolt’ visited by silver spotted skipper), love-in-a-mist and love-lies-bleeding offer romance, drama, and fragrance to the garden, and they draw pollinators!

1. You’ll Have Many More Choices

Cornell’s Vegetable Varieties for Gardeners, a citizen science program, describes 574 pepper varieties, 370 lettuces and an astonishing 910 types of tomatoes. Only a fraction of these can be bought as seedlings. You’ll have a hard time finding the delicious and highly rated ‘Carmello’ tomato in a pot, or one of the great tasting new container tomatoes, or ‘Topepo,’ a sweet Italian heirloom.

The same with flowers. Your local nursery rarely offers interesting and unusual plants such as bells of Ireland (Moluccella laevis), or delicate love-in-a-mist (Nigella damascena), or even easy-to-grow, evening scented four o’clocks (Mirabilis jalapa).

2. You Can Control Quality

basil opal & thai lemon
Seedlings started indoors will thrive when provided with plenty of light and enough water to keep the soil moist but not soggy. Begin feeding them with a half-strength liquid fertilizer when they have two sets of leaves. Above, Thai Lemon basil and Dark Opal basil, grown from seed.

Even if you are lucky enough to find your desired tomato, pepper, and flower varieties as plants, should you buy them? The answer depends on how well you know the grower. Seedlings that have dried out at some point in their lives or become root bound will not perform well in the garden. When you grow your own you’ll know that they’re being well cared for until the time is right for planting, and that they’ve been grown without unwanted chemicals.

Plants grown under poor conditions will not produce adequate foliage or yields.
– UMD College of Agriculture and Natural Resources

3. Growing From Seed Is Easier

Larkspur and dill bloom in unison in early summer. Both are easy to grow by sowing seed directly in the garden.
Larkspur and dill bloom in unison in early summer. Both are easy to grow by sowing seed directly in the garden.

It’s a fact: many plant varieties are more successful when grown from seed sown directly in the garden. These include root vegetables, herbs in the carrot family such as cilantro and dill, baby salad greens of any kind and flowers that are best sown very early in the season, such as larkspur, bells of Ireland, and love-in-a-mist.

Other vegetables and flowers are so easy to grow from seed that buying seedlings makes little sense. Squash, melons, beans, peas, sunflowers, zinnias, nasturtiums and cosmos are a few.

Garden centers routinely sell small blooming transplants. Flowers such as zinnias, marigolds, and celosias will do better in the long run if planted before they bloom—yet another reason to buy and grow seed!

Read packets of beans, root vegetables, greens, and other plants for seedling spacing. Sca-er seeds of greens and root vegetables about an inch apart in the garden soil, otherwise plants will be overcrowded and will not thrive.
Read packets of beans, root vegetables, greens, and other plants for seedling spacing. Scatter seeds of greens and root vegetables about an inch (2.5 cm) apart in the garden soil, otherwise plants will be overcrowded and will not thrive

Plants Best Sown Directly In Garden Soil

  • Baby greens: lettuce, arugula, spinach and others
  • Beans and peas
  • Corn
  • Roots: beets, carrots, radishes, turnips and others
  • Scallions
  • Squash, melons and cucumbers
  • Swiss chard
  • Annual herbs: basil, cilantro, dill
  • Many annual flowers: cosmos, nasturtiums, sunflowers, zinnias, cleome, amaranth, celosia and others
  • Flowering vines: morning glories, scarlet runner Bean, hyacinth bean and others
  • Flowers sown in fall or early spring, such as larkspur, bells of Ireland, bachelor buttons and love-in-a-mist

4. You’ll Save Money

Community garden plot showing cabbage and kale.
A 2008 National Gardening Association study estimated that U.S. food gardening households spent an average of $70 a year on their gardens. With a yield of about 1/2 pound of produce per square foot, an average 600-square-foot garden can produce 300 pounds of produce worth $600!

Lush, extravagant swaths of color are within your budget. A whole packet of zinnia, sunflower, or marigold seeds can be purchased for about the same cost as a six-pack of seedlings, or even a single seedling in some markets.

A productive vegetable garden can feed your family all year for a fraction of what you would pay for equivalent produce at your local grocer or farmers’ market. An added advantage of buying seeds rather than plants: you’ll be able to sow succession plantings of greens, beans, and other crops for a second harvest!

All the flowers of tomorrow are in the seeds of today.
~ Ancient proverb

5. It’s Fun to Do!

Tomato seedlings in multipacks.
Moisten the soil mix to the consistency of a wrung out sponge before planting seeds in multipacks or recycled containers from the grocery store. A good rule of thumb for starting tomatoes (above), peppers, eggplants and annual flowers: plant two to three seeds in a cell and thin to one when the seedlings grow their first set of true leaves.

It’s also magical, and gives you a feeling on independence and, yes, power, to watch a seed germinate and grow into a healthy seedling, connecting you to nature even as frigid weather may be confining you to the indoors. 

The real question is … 

Why not grow your garden from seed?

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Yes, You Can Let Vines Climb Trees!

Climbing hydrangea with white flowers climbing up a tree.

A climbing hydrangea (Hydrangea petiolaris) growing on a tree: nothing could be more natural! Photo: Dave Epstein, @growingwisdom

What is it that gardeners have against letting climbing plants—vines if you prefer—clamber into trees? This is how most of them live in the wild, yet in the gardening world, at least in North America, such a use seems to be considered an anathema. (Brits seem to be more open to the idea while, if you want to see beautiful marriages of climbing plants and trees, try visiting German gardens. German gardeners seem to fully understand the concept!)

True enough, in certain public gardens, there are magnificent specimens of trees decorated with climbing hydrangeas, climbing honeysuckles or clematis, but even so, few gardeners seem to think that the concept could be adapted to a home garden. The belief seems to be that a climber can’t be grown anywhere other than on a trellis, arbor or pergola. Letting a climbing plant grow up a tree, claim many gardening websites, will kill it. 

Well, that’s nonsense! True enough, you wouldn’t let an overly aggressive climber loose on a small or weak tree (more on that below), but then, when you garden, you wouldn’t plant a dominating, weedy plant next to a fragile, rare specimen, would you? Gardening is all about marking careful matches. And there are good combos of trees and climbers and bad ones.

Which Climbers to Choose?

Self-clinging climbers—ones with adhesive pads or aerial roots (such as Virginia creeper, Boston ivy, climbing hydrangea, and English ivy)—are the easiest to use this way, although they tend to be quite dominant climbers, best limited to large, fully grown trees. The advantage is that they will climb all on their own, because they cling onto any rough surface and, in fact, specifically evolved to fasten onto bark.

Dutchman’s pipe with heart-shaped leaves climbs up a tree.
Dutchman’s pipe (Aristolochia macrophylla) creates a wonderful effect when allowed to climb a tree. Photo:

The twining stems of certain other climbers, such as bittersweet (Celastrus spp.) and Dutchman’s pipe (Aristolochia macrophylla), form very broad loops and can thus encircle a tree trunk quite wide in girth, allowing them to therefore climb even massive trees with any other help.

Mixture of clematis climbing a tree.
It often takes a bit of cordage or wire mesh to help some climbers, like these clematis, begin their climb up a tree. Photo:

That isn’t the case with all twining climbers. Many, such as clematis and most annual climbers, like scarlet runner bean (Phaseolus coccineus) and morning glories (various species of Ipomea), can only wrap themselves around fairly slim supports: twine, netting, moderately thin branches, etc. Planted at the base of a tree, they often try to climb, then lose hold and slide down: not exactly the effect you want! You need to provide them with wire netting or some sort of cord to wrap around until they reach at least the lower branches of the tree. From there on in, though, thanks to the thinner branches found there, they can then start to climb on their own.

Rosa 'Blue Magenta' climbing a tree.
You need to attach climbing roses (here Rosa ‘Blue Magenta’, a rambling rose) to the tree trunk at first, but once they’ve reached the lower branches, they’ll generally grow upward with no other support. Photo:

Finally, there are climbing roses (Rosa spp.). As most gardeners already know, they really don’t climb on their own. You always need to tie their rather rigid stems to their support to start them off in the right direction, even when you grow them on a trellis. The situation is no different when you want them to grow up a tree. Afterwards, as with weaker twining climbers, once their branches start to mingle with the tree’s branches, they’ll no longer need your help.

Helpful Hint: When looking for climbing roses to grow on a tree, consider rambling roses. Not that well known in North America, they have taller, more flexible stems than classical climbing roses and are the best types for training up a tree. You’ll most likely find them in specialist rose nurseries.

How to Plant a Climber Under a Tree

Illustration of how to plant a climber at the drip line of a tree
To make planting easier, place the climber away from the trunk, out around the tree’s drip line, then direct the stems toward the trunk. Ill.: &

Small trees rarely have much of a root system and if you want to plant a climber near their base, that’s usually quite doable. However, if you want to plant a climber at the base of a large, well-established tree, planting at its base is going to be very difficult. Huge roots will likely thwart your efforts at digging a suitable hole; plus conditions will be too dark, dry, and low in nutrients to give the climber a good head start. So, cheat a bit and plant the climber out close to the tree’s drip line (the outer edge of its leafy canopy), where roots will be less dominant and ressources, more abundant. Then direct the long stems toward the trunk, securing them to the ground with stakes if you have to (they’ll usually root into the soil there on their own once they start growing). Once they make contact with the trunk, you’ll see that most of them will start to climb with surprising vigor, as if they had waited all their life for a chance to climb … which is, of course, exactly the situation.

A Reasoned Choice

Trees completely overgrown with kudzu.
Kudzu (Pueraria montana lobata) is far too aggressive to grow up a tree! It will likely engulf its host … and all other nearby trees as well! Photo:

Obviously, you have to be logical in your choice of climber.

If a climber is invasive in your area, such as kudzu (Pueraria montana lobata), Japanese honeysuckle (Lonicera japonica), or Oriental bittersweet (Celastrus orbicularis), all considered undesirable invasive species in many parts of America and Europe; obviously, they shouldn’t be planted. And English ivy (Hedera helix), perfectly acceptable in Europe where it’s native, cannot be recommended in those parts of North America where it self-sows too aggressively. But there are dozens of other climbing plants you can use that nobody considers invasive.

Climbing rose with red flowers clambering into an apple tree.
A less vigorous climber, such as a climbing rose, makes a better choice for a small tree like this apple tree than would a strong, tall, dominant climber like Virginia creeper. Photo: http://www.fotocommunity.dewers clambering into an apple tree.

Also, vigorous and very dominant climbers, such as Boston ivy (Parthenocissus tricuspidata), Virginia creeper (P. quinquefolia) and American bittersweet (Celastrus scandens) can take over and choke out young trees or trees of naturally small size, such as Japanese maples (Acer palmatum) or crabapples (Malus spp.). Limit their use to large, mature trees (full-grown oaks, maples, lindens, etc.). For small trees, pick climbers of lesser vigor, such as climbing roses and clematis.

Also, only plant varieties that are well suited to your climate, especially your hardiness zone, and your growing conditions. Not much will come of planting a tropical climber like bougainvillea (Bougainvillea spp.) in the cold North!

However, if you pick carefully, why not plant climbing plants to give your trees a bit of punch? Two plants sharing one space? Ma Nature does it all the time, so why shouldn’t you?

Adapted from an article first published on February 24, 2015.

How Seeds Get Around

Dandelion seed head with seeds blowing in the wind.

Plants have developed ingenious methods to ensure the dispersal of their seeds. Dandelions, for example, take advantage of the wind. Photo:

At this time of year when gardeners are preparing to sow vegetables, herbs and flowers for the summer garden, it can be interesting take a deeper look into a most fascinating natural phenomenon: how seeds are dispersed. Because a plant doesn’t produce seeds for the simple pleasure of doing so: they’re its main way not only of reproduction, but also of getting around.

If all seeds fell only by gravity to the base of the mother plant and then stayed put, they might end up in such deep shade they couldn’t germinate. That just isn’t workable. So, over the millennia, plants have had to find other ways of making sure their seeds get further afield and, in doing so, they developed many fascinating dispersal techniques.

Blowin’ in the Wind

Poppy capsule showing the openings from which the seeds are shaken.
It’s the wind shaking poppy capsules that tosses their seeds far and wide. I mean, the capsule even looks like a saltshaker! Photo:

Many plants rely on the wind to disperse their seeds. Poppy seeds, for example, remain in their capsule until a blustery day makes them wobble back and forth, tossing them in all directions.

Illustration of a maple samara and of dandelion seeds blowing in the wind.
Maple samaras and dandelion seeds also rely on the wind for their dispersal. Ill.: George Retseck,

Many seeds come with wings to help them get about. What child doesn’t know about what we used to call “helicopters” when I was a kid, the samaras of the maples which, as they fall, spin and are carried far away from the mother tree? Even more effectively, some “wings” have become light and feathery, making the seed almost as light as air. The dandelion, with its “parachute”, is an expert in getting around: some seeds traveling up to 100 kilometers strictly on wind power.

Other plants opt for seeds so small and light they don’t need wings. They’re essentially as light as the air and easily carried afar by even the slightest breeze. That’s the case with orchids, that produce the smallest seeds in the world, so light they can travel several kilometers. Fern spores, while technically not seeds, are even lighter and travel even further. Ferns have already been found sprouting on the freshly cooled lava of a new volcanic island located over 3,000 km from the nearest population of that species!

Water as a Tool

For aquatic or riparian plants, water is often a major seed carrier. Their seeds have the ability to float, sometimes for months, until a wave drops them in a suitable habitat.

Coconut floating in front of a tropical island.
Although bulky and heavy on land, coconuts float readily and count on waves and tides to move them about. Photo:

The coconut palm (Cocos nucifera) has worked its way through much of the tropical world thanks its highly buoyant nuts. You may have noticed that when coconut palm grows on a beach, it often leans out over the sea, ensuring that its seeds drop into the water when they fall from the trunk. 

On the other hand, this tropical fruit also grows inland … but only when it’s planted there by human hands, because without water to carry them away, its large nuts drop uselessly to the ground, accumulating in piles at the foot of the mother plant where, for lack of sun, most of them either germinate, but fail to thrive or simply rot.

Harnessing Animal Power

Bird eating berries.
Birds often carry seeds from one place to another … in their droppings! Photo: Chris Child, Unsplash

Many plants have learned to rely on other, more mobile carriers—animals!—to help disperse their seeds. Most of these plants have edible seeds or fruits; the animal collects their seeds and, with a bit of luck, carries them somewhere else to eat them, ensuring their spread.

But this kind of dispersal can be a bit tricky. After all, if the animal carrier digests the seed, that gives the plant no benefit. So, plants have learned to be devious. Often the fruit has edible flesh, but the seed is either inedible or less interesting than the fruit and therefore dropped, thus sowing the seed. In other cases, the animal actually does swallow the seed, but its hard coat allows it to travel intact through the animal’s digestive system to be discharged later in its droppings. In fact, many seeds will not germinate without passing through the digestive system of a bird or mammal.

Many fruits even tell their hosts that they are ready to be harvested by drastically changing color. That’s why cherries and strawberries turn red when they’re ripe: it’s to tell l birds and other animals that it’s time to come and eat them!

Chipmunk carrying peanuts.
In my yard, chipmunks regularly carry peanuts from a neighbor’s bird feeding station to my garden, a good 40 m (130 feet) away, so I find peanut plantts sprouting in all my flowerpots! Photo: Rick Romell,

However, some seeds place their trust in the animal’s shoddy memory. The seed inside a walnut (Juglans spp.) is perfectly edible and digestible, as the embryo in the center of the acorn (seed of the oak tree, Quercus spp.), but both nevertheless rely on squirrels, woodpeckers, jays and other birds and mammals for their dispersal.

It seems rather dangerous to give your precious seeds to an animal—and a greedy one at that!—that will gladly eat and digest the its contents, but there is method to these plants’ madness. Their trick is to produce far more nuts than the animal could possibly eat all at once, so it gathers and stores the excess nuts for the winter, burying them in safe places. Sometimes the animal then forgets where it put them, sometimes it stores too many and doesn’t need to come back and harvest all of them … and sometimes it simply doesn’t make it through the winter. Whatever the situation, this method ensures that enough conveniently planted walnuts and acorns are never actually eaten and thus ensure the dispersal of walnut and oak trees.

White dog with burdock on its head.
Burdocks are just one of many plants that ensure their dispersal by clinging to the hair of animals. Photo: sodO,

And who doesn’t know that some seeds have learned to hitch a ride on animals in order to get around? Burdocks, with their Velcrolike hooked teeth, cling to animal hair—and our clothes!—and thus travel far and wide. As they are irritating, however, the animal scratches itself to remove them, knocking the seeds free … and that way they sometimes fall several kilometers from their place of origin.

Some aquatic plants also have hooked seeds that grip the feathers of waterfowl, allowing them to travel from one lake to another.

And did you know that there are even seeds that travel … by car? Vehicles easily transport certain seeds over long distances, stuck to the soil that attaches to the frame or tires. One study found that the most common seeds dispersed by automobiles in the UK were plantain (Plantago major), annual bluegrass (Poa annua), rough bluegrass (Poa trivialis), stinging nettle (Urtica dioica) and pineapple weed (Matricaria discoidea). Who knew?

Carrier Exclusivity Can Be a Double-Edged Sword

But there can be a problem if a plant comes to depend too heavily on a specific animal for its dispersal. What if the animal carrier goes extinct?

Illustration of a giant sloth.
The disappearance of the giant sloth is believed to have led to the extinction and near extinction of many trees bearing large fruit. Ill.:

That’s what happened to many tropical fruit trees in the Americas. Botanists exploring South and Central America in previous centuries were confused by the discovery of many trees with very large, fleshy, and apparently delicious fruit, evidently designed to be eaten and dispersed by a very large animal, but which no longer seemed to be finding takers. In fact, all of these trees were in danger of extinction because they could no longer reproduce effectively. 

The conclusion? That humans, upon arrival in the New World, had hunted fruit-loving giant sloths, once abundant throughout the region, so effectively they went extinct, leaving their favorite trees without a means of dispersal. Many isolated trees found here and there were the last of their kind!

Avocados hanging in an avocado tree.
If the avocado tree (Persea americana) didn’t disappear with the giant ground sloth, it’s thanks having been adopted as a fruit tree by humans. Photo:

Fortunately, the new invader, humans, adopted some of these fruits which are now only found in cultivation. Such is the case with the avocado (Persea americana) we now find abundantly in our supermarkets.

Going Ballistic

Impatiens capsule that explodes when hit by a drop of water.
Impatiens seed capsules burst open explosively when touched, here by a drop of water, shooting the seeds long distances. Photo: Smithsonian Channel

Some plants have a surprising technique to ensure their dispersion: they have explosive capsules. This is called ballistic dispersal. 

When the seeds are ripe, the capsule twists or bursts suddenly, throwing the seeds a good distance. The impatiens (Impatiens spp.), whose capsules burst open shooting seeds everywhere, much to the delight of children, falls into this category, and geraniums (Geranium spp.) and violets (Viola spp.) have a similar system. 

Squirting cucumber explosively expelling liquid and a long series of black seeds.
The squirting cucumber (Ecballium elaterium) is another plant that forcefully expels seeds and in a most surprising way, ejecting a stream of liquid containing its seeds for distances up to 6 m (18 feet). Photo:

The most explosive of all is perhaps the sandbox tree (Hura crepitans) that creates a sound like dynamite when it shoots off its seeds. Not surprisingly, it’s also known as the dynamite tree!

Human Intervention

Other plants have come to depend on humans for their dispersal. There’s even a name for this phenomenon: anthropochory.

Display of seeds on a wooden store rack.
Seeds harvested all over the world are brought together in this seed pack display. Photo:

Vegetables, cereals and garden flowers rarely disperse seed on their own anymore: they rely on humans for their reproduction. Seed companies harvest their seeds and sell them in seed packs, bags or boxes to the gardeners and farmers who then sow them. Thus, these plants can travel thousands of kilometers. Indeed, the tomato seed you sow this spring might well have travelled from Israel or Thailand.

Go for it, plants! Make the humans do your bidding!

Ear of corn wide open, exposing the kernels.
Corn (maize) is no longer capable of reproduction without human help. Photo:

Some domesticated plants are so dependent on humans for their dispersal that they are no longer able to reproduce on their own. Corn or maize (Zea mays), considered the most “evolved” of cereals (at least from a human point of view), is so far removed from its ancestral form that its seeds no longer fall off the cob without help and thus cannot germinate unless humans pluck them free. So, if human beings were to disappear, that would be the end of corn.

The next time you hold a bag of seeds in your hands, in addition to marveling at the idea those tiny, inert, hard-shelled organs that will, in just a few months, turn into delicious vegetables and beautiful flowers, also think of the path they have taken to get from Asia, South America or Australia to your garden. It’s just another little miracle of daily gardening life!