Cacti: August Houseplant of the Month

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Whether it’s their trendy geometric shapes or their air of unapproachability, cacti are exciting houseplants that have a big impact on an interior decor and often live alongside their owners for decades. This classic plant’s comeback is particularly due to its (undeserved) reputation as needing no care as well as its unusual appearance.

Origin of Cacti

Distribution map of cacti in the wild. Ill.: reddit.com

The spiky plants that we call cactuses or cacti (both plurals are acceptable) are from the Cactaceae, a large plant family native throughout much of North and South America, with a strong concentration in Mexico. The plants mainly grow in dry or desert regions where they have adapted brilliantly to the extremely arid conditions and positively thrive where most other plants would have trouble surviving.

The name cactus is derived from the Greek word “kaktos”, which means “spiky plant”. Every cactus is a succulent, but not all succulents are cacti. What cacti share with other succulents is the ability to store moisture in their thick fleshy stems. These reservoirs are used to bridge periods of drought.

Cactus roots may be confined in a pot in culture, but in the wild, they are far-reaching and are usually found just below the surface in order to slurp up as much water as possible during those rare rainy periods that allow them to grow.

Notice that, with very few exceptions, cacti have no leaves. They lost them as they adapted to growing under conditions of great aridity. Instead, they carry out photosynthesis via their green stems. The cactus’ outer skin has a layer of wax that minimizes evaporation.

The woolly bumps on cactus stems are areoles. Only cacti have them. Photo: Steve Cook @Polypompholyx

What distinguishes cacti from all other succulents is that their stems bear areoles: the place where the leaves should actually be. These look like fuzzy little pads usually placed quite symmetrically on the stems. From these areoles grow spines, long hairs, new stems and, eventually, flowers. No other plant has areoles and looking for them is the best way to tell a cactus from other stem succulents, like euphorbias.

Cacti have been cultivated for centuries, as outdoor plants in mild climates, but elsewhere mostly as houseplants. That said, there are hardy cacti, some tolerant of extreme cold, but most cactus species are best grown as indoor plants everywhere outside of the very mildest climates.

What to Look for When Buying Cacti

With cacti, there’s lots to choose from in just about any garden center.
  • Price is largely determined by size. Small cacti are less expensive than large ones as they cost less to ship. Some cacti are naturally small and will always remain so; others will grow considerably over time. If you want a small cactus that will grow large, a young columnar cactus (see below) would make a good choice.
  • Age is also a factor in pricing. Cacti that take years to grow to a saleable size will cost much more than fast-growing cacti. That often explains why two similar-sized cacti can have such a difference in price.
  • Check that the cacti are free of mealybugs on both the plant itself (the body) and the root system. With their woolly white waxy coating, these oval sap-sucking insects are one of the most common pests in cactuses and are difficult to get rid of. Leave infected plants in the store.
  • Also check for red spider mites (looking like dust particles moving over fine webbing), aphids, scale insects and thrips. 
  • Check for damages to the plant’s stem and make sure that the root system is intact. If the plant has been kept too wet for a long time, it may show a soft spot at the base of its stem, the first sign of rot caused by fungi and bacteria. Avoid such plants.
All these flowers were glued on to push sales. Photo: http://www.plantinterrarium.com
  • Look at any cactus flowers with suspicion. Often such blooms are simply dried strawflowers glued onto the stem and the glue used permanently damages the plant. To check, gently push the petals upward and check underneath the blossom. Real cactus flowers will be attached to the main stem by a shorter, usually spiny stem, not by glue.
  • If you want a cactus that will bloom readily, ask the clerk to help you choose. Many cacti are reluctant to bloom indoors.
Spray-painted cactus are now widely available, unfortunately. Photo: pentagrambunny, reddit.com
  • Be wary too of plants with oddly colored spines. White, golden yellow, gray and brown are normal spine colors, but purple, blue, orange, fluorescent yellow, etc. are not. It has become popular to “enhance” cacti by spray-painting them. This is harmful to the plant and such plants should be left in the store.
Cactus are very unhappy in a terrarium setting and usually die slowly. Photo: succulentsnetwork.com
  • Avoid cacti planted in terrariums and bell jars. With no drainage hole, they are almost impossible to water, and they hate the high humidity and poor air circulation found there. They usually die slowly over a period of several months.
  • Spiny cacti can be hard to handle. Have the clerk handle and wrap your plant for you. 

Cacti Range

With some 1,800 species, the range of cacti is enormous and extends from tiny sleek shapes through bizarre massive pillars, and from soft gray hairs through to big sharp spines. Many cacti are sold in mixed trays, particularly the smaller sizes. The species that are most commonly sold by name are Echinocactus, Ferocactus, Gymnocalycium, Opuntia and Mammillaria.

Cactus can masquerade as other succulents, but their areoles give them away. Photo: mashtalegypt.com, montage: laidbackgardener.blog

Succulent Euphorbia species closely resemble cactuses and are often sold in the same mixed trays. It’s easy to spot the difference: euphorbias thorns grow directly out of the green body, while those of cactuses they grow out of the areoles, the fuzzy bumps mentioned above. Also, many euphorbias have small leaves while cactus rarely do.

Desert Cacti or Forest Cacti?

Desert cacti. Ill.: etsy.com

Most cacti are desert dwellers or at least adapted to intense sun and arid conditions. These usually have the thickest stems, abundant spines or hairs, and will require full sun and well-spaced watering indoors. They are listed below as (dc).

Forest cactus. Photo: spokaneplantfarm.com

Another group of cacti lives in forests in the wild. Most are epiphytes (grow on tree branches) and have thin or flattened branches, few or no spines and a trailing habit. In culture, they require less light and more regular waterings, more like a spider plant than a typical cactus. Below, they are indicated by the abbreviation (fc).

A Wide Range of Shapes

Cacti can be classified by genus, origin or shape. The following groupings can give you an idea of their shapes:

Prickly pear cacti (Opuntia spp.).
  • Prickly pears, also called beavertail or bunny ear cactus (dc): They have flattened, paddle shape pads. Only the genus Opuntia has this form. They have either long spines or apparently no spines at all. Beware, though, as their seemly innocuous areoles hide tiny spines called glochids that break off and penetrate the skin.
The Peruvian apple cactus is a typical columnar cactus (Cereus repandus). Photo: http://www.palmenmann.de
  • Columnar cacti (dc): Upright shapes that start small and develop a real pillar shape later (Pachycereus, Cereus and others).
Various mammillarias (Mamillaria spp.) with real flowers. Mammillarias usually bloom quite readily after a cold, dry winter. Photo: http://www.uhlig-kakteen.de
  • Globe cacti (dc): Attractive globe shape. May grow individually or in columns. (Echinocactus, Mamillaria).
Various mistletoe cactus (Rhipsalis spp.): Photo: worldofsucculents.com
  • Trailing cacti (dc and fc): With long stems arching down (Aporocactus, Rhipsalis).
Orchid cactus (Disocactus ackermannii, formerly Epiphyllum ackermannii). Photo: worldofsucculents.com
  • Orchid cacti (fc). Epiphytic cacti with spreading, trailing, triangular or flat stems, usually spineless (Epiphyllum, Selenicereus). Grown for their huge flowers (seasonal).
Thanksgiving cactus (Schlumbergera truncata cv). Photo: Peter Coxhead, Wikimedia Commons
  • Holiday cacti (fc): Arching, flattened, spineless stems bearing bright flowers at Thanksgiving, Christmas and Easter (Schlumbergera).
Brain cactus ((Mammillaria elongata ‘Cristata’). Photo: mld-succulents.com
  • Crested cacti (dc): Mutated cacti taking on a brainlike shape (Mammillaria elongata ‘Cristata’ and many others).
Albino forms of Gymnocalycium mihanovichii friedrichii grafted onto a photosynthesizing cactus. Photo: anaturalcuriosity.org
  • Grafted cacti (dc): Two species grafted onto one another. Often the top cactus (Gymnocalycium), brilliantly colored (red, pink, orange, yellow, etc.) is actually an albino and can’t grow on its own.

Care Tips 

Severely etiolated cactus desperately trying to tell its owner it needs more light. Photo: anskuhh s, houzz.com

Cacti are often said to be easy-to-grow plants that will thrive anywhere. This myth is largely based on their capacity to “hold on” for months, sometimes even years, even under the most inappropriate conditions. Even as the owner is pleased with the results, the plant is often dying, living on its reserves, but not clearly showing its distress. When death finally comes, it often stuns the owner.

If treated as a throwaway plant, designed to be tossed into the trash when it stops looking good, a cactus can be placed anywhere, sun or shade, in heat or in cold. Water it when you feel like it or not at all. If you find that acceptable, why not buy a plastic plant? It will last longer and won’t have to suffer a lingering death.

Here are some tips on how to really keep cacti happy and healthy:

Most cactus have to be grown in front of a sunny window in order to thrive. Photo: http://www.westfargopioneer.com
  • Desert cacti require intense light (full sun), especially spiny and hairy ones. Forest cacti, like holiday cacti, tend to be better choices for lower-light situations. Given the proper light, most cacti are easy to maintain and can live for decades.
  • But proper watering is also necessary. Desert cacti will not tolerate overwatering and have to be allowed to dry out thoroughly before watering again. So, benign neglect is best. If you’re not sure whether a cactus needs watering, it probably doesn’t. Lift the pot to tell: it will be considerably lighter when it is fully dry. Or use a moisture meter, watering only when the dial is well into the red zone (dry). 
  • Water forest cacti more regularly, although still only when the soil is dry to the touch. You can water them when the soil is barely dry rather than waiting until it is bone dry.
  • When you do water, do so thoroughly, soaking the root ball, although never letting the plant sit in water. Giving just a spoonful or two of water at a time is a common error and causes long-term stress. 
  • Cacti can tolerate hot, sunny spots in the summer and also thrive outdoors on the patio or balcony. They prefer cool conditions, although still with intense light, in the winter. A cold, dry winter, down to nearly freezing, can encourage some desert cacti to bloom.
  • Cactus are very tolerant of negligence and can be left on their own with no care at all on a bright windowsill when you’re absent. All will tolerate at least a month without watering; desert cacti, often 5 months or more, making them an ideal choice for Snowbirds.
  • If the plant needs repotting, use a well-drained, fairly nutrient-poor soil. Special cactus soil is available for this. Since cactus don’t tolerate overwatering, the pot must have a drainage hole.
  • Place the prickly cacti in a safe place if there are children or pets around. Those spiny can be nasty!

Display Tips

Cactus gardens are a fun way to grow cacti.
  • One cactus is never enough! The plants speak to the imagination best if different species are displayed together.
  • Cacti make great choices for a student room or an office, as they can tolerate long periods of negligence.
  • The various sizes on offer—from mini to massive—make them ideal gifts.
  • Cactus gardens combining various species are attractive and exotic. They do best in open bowls rather than terrariums.
Artisan pots can make cacti really stand out. Just make sure they have a drainage hole!
  • Cacti can be used both in traditional interiors and in a modern setting. A folkloric look is the bang-on trend and doesn’t need to be restricted to South American decors. Artisan pots with folklore patterns and colors create a cheerful setting for the rather stoical cactus. 
  • The plants can also be used for certain summer or holiday themes (beach, Mexico, indoor rock garden, etc.).

Enjoy your cactus and … long may it live!

Text adapted from a press release by Thejoyofplants.co.uk.
Unless otherwise mention, photos also by Thejoyofplants.co.uk.
Styling by Elize Eveleens, Klimprodukties

5 Ways To Enhance The Look of Your Patio

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By Robert Baker of Outsidepursuits.com
Photo: Rhys Ludlow, Pixabay

Is your patio looking tired and dated? Before you invite over your friends and neighbors, make it shine with these 5 easy enhancements.

#1. Clean up your act

Set aside any outdoor furniture or other movable objects to examine the condition of your patio. If it’s more than a few years old, it probably needs a little TLC. 

Weeds are a common problem, sprouting between paving stones or cracks in the cement. Use a rusty old screwdriver to dig them out. If you have a few small weeds and don’t want to damage the remaining mortar, mix 2 parts boiling water to 1 part salt to create a simple and natural weed killer you can apply to the infestation.

Clean any remaining holes thoroughly then fill them with a mix of 3 parts sand to 1 part cement bonded with a little water. Tamp down the mix with a trowel. 

Stains soaked into concrete patios can be unsightly but applying concrete acid stain can revitalize your patio’s surface by staining the whole area in a single color with unique swirly patterns. A pressure washer is a great investment not only for washing your car but also for deep cleaning your patio surface. An afternoon with a pressure washer can leave your patio looking as good as new.

#2. Furnish your floor

After your patio has been cleared of weeds and cleaned, you can put your furniture back. However, are you happy with what you see? The furniture on your patio determines what it looks like, so you want furnishings that are both aesthetically pleasing and practical for your purposes. 

Recently there have been many innovations in outdoor furniture that mean you can truly transform your patio into an outdoor living room by choosing patio furniture you love that looks as good as anything in your living room. Wicker, rattan, or plastic patio armchairs and couches are a must for relaxing outdoors. 

With an outdoor table and chairs, you can create an al fresco dining experience at home. And with Bluetooth speakers designed for outdoor use, you can host fantastic parties in your backyard. If you enjoy your me-time and like to curl up with a good book, why not invest in a hammock. You don’t need a pair of trees to hang a modern hammock since many come with a frame.

#3. If it’s hot in the kitchen…

Some people enjoy staying out on their patios so much that they’ve moved their kitchens outside. With so many companies now manufacturing high-quality catering equipment designed to withstand the elements, there’s nothing you can’t buy to make your outdoor kitchen just as good as your indoor one. 

Patio kitchens are especially great if you want to entertain outdoors because it means you won’t have to keep going in and out of your house to serve the food to your guests. In summer, your kitchen won’t get too hot, and you can appreciate the fresh air and flowers outside while you cook. 

If you want to keep things simple and affordable, you can just purchase a portable barbecue for your patio. Fully equipped outdoor kitchens are a major investment and can cost more than a traditional indoor kitchen. 

#4. Put a lid on it

If you want a little protection from the sun on your patio, consider having an expert install a garden awning. With modern designs, you can roll your awning out during the midday heat and roll it back in again when you want to catch some rays. These are especially useful if you want to host dinner parties outdoors when other factors, such as bird droppings or wind, might disturb your eating experience.

Alternatively, shade sails have recently grown in popularity. They offer the advantages that you don’t have to attach them to a wall, and they are more affordable than awnings. However, their disadvantages are that you require 4 fixed points to tie them, such as handy trees, and they’re not so easy to deploy or to put away.

Some people like to install a pergola over their patio to add a little shade. However, this is a relatively expensive option, especially if you’re planning to get someone else to build it. 

#5. Go potty

Your patio is in the garden, so why not celebrate that with a fine selection of flowerpots? When choosing flowerpots, be like McDonald’s and go large. Big plant pots make a statement and stand out on your patio. They also provide the kind of space you require for impressive feature plants, such as miniature cherry blossom trees.

There is such a wide range of flowerpots available today that you can choose designs to suit any taste. You can color coordinate them to your patio furniture or opt for plain Italian terracotta pots that blend into the background and leave the flowers they contain to add color to your day. 

The Fascinating History of the Lawn

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The Green Carpet at Versailles was one of the first lawns designed strictly for show. Photo: Remi Jouan, Wikimedia Commons

Conqueror of the suburbs, the lawn has quietly made its place into our everyday life. Here’s its fascinating history, from the medieval village greens to the garden of Downton Abbey and the arrival of inexpensive lawn mowers.

If there is one element that dominates our suburbs, it’s the lawn. This carpet of greenery stretches over vast areas, dominating the landscape as soon as you leave the city’s core of concrete and asphalt. Not many houses don’t have one … and around many homes, it is indeed the only living decoration. But where does this overwhelming popular fashion come from?

The Beginnings of the Lawn

Not many village greens still remain today and the few that do exist almost never serve as pasture for cattle and sheep anymore. Photo: Kevin Rae, Wikimedia Commons

The first lawns were likely village greens or town commons, found throughout Europe in the Middle Ages. The citizens of the village had the right to graze their cows, sheep, horses, etc. on this communal pasture. The constant grazing produced a very short meadow which was called lawn, from the Middle English launde, for glade or opening in the woods.

The aristocracy adopted a similar green space around their castles: again, one simply maintained by grazing animals. The idea at the time was said to show that the owner was a good Christian (a reminder of the many references to sheep, shepherds and pastures in the bible), but in this period of almost constant war, a grassy space free of tall vegetation also let you see the enemy coming from afar.

French- and English-Style Gardens

When André Le Nôtre designed the gardens of Versailles for Louis XIV at the end of the 17th century, launching the jardin à la française (French formal garden), he included a vast “green carpet” (also called “Royal Alley”), a parterre of vegetation kept mowed by gardeners with scythes and located on the garden’s main axis. This was probably one of the first strictly ornamental lawns in history.

The cool, humid climate of Western Europe made such an innovation possible. It would be difficult to imagine lawn having evolved in the hot, arid climates of Mesopotamia or Egypt. 

Soon such “green carpets” began to spread all over Europe along with the French formal style, because nobles wanted to imitate the Sun King.

But the reign of the French formal garden—highly geometric and dominated by precisely trimmed hedges, designed to show the total domination of man over nature—was actually short-lived. It was almost wiped off the map less than a century later with the arrival of the English landscape garden, under the influence of English designer Capability Brown (1716–1744).

The English landscape garden is characterized by a bucolic landscape dominated by a green lawn. Here, Stourhead garden in England. Photo: Luke H. Gordon, Flickr

This style offers a return to a more natural look, a rediscovery of nature … but of nature as improved by human hands. Brown designed sweeping pastoral landscapes marked by artificial hills, asymmetrically shaped lakes, serpentine streams, seemingly natural groves, etc. Connecting all these elements was an undulating green lawn. Maintenance is still mainly done by the cattle and sheep, which were prevented from wandering into the manor house by “ha-has”, ditches specially designed so as to appear invisible from a distance. 

Do you remember the layout of the grounds, with its endless green lawn and tall evergreens, of the TV series Downton Abbey? That was a pure English landscape garden.

Tea served on the lawn on Downton Abbey. Photo: PBS/Masterpiece Classics

The idea of the English landscape garden was to show that the owners could afford to devote vast amounts of highly valuable land to purely aesthetic purposes. They often held garden parties and lunches on the grass with hundreds of guests. Only the richest could afford such luxury.

But with the arrival of the first lawn mowers, timidly in the 1830s, but especially from 1860 on, first the gentry, then the middle class took the style for themselves. Now there was no need to hire teams of peasants wielding scythes, one man could mow a vast lawn over just a few days. 

So, the price of maintaining a lawn dropped considerably. Not only could the castles and manors of the landed gentry have vast lawns, but simple country homes as well.

Lawn sports—here a game of lawn bowling in 1870—became popular, further stimulating the need for flat, green lawns. Photo: Southampton Old Bowling Green Club

By the Victorian era, even as the lawn was taking over upper-class abodes, lawn sports—croquet, tennis, lawn bowling, polo, etc.—were also becoming popular and they required flat grassy surfaces. Yet another reason to put in a lawn!

Also new to the time was the revolutionary idea that it was healthy for both body and mind to be outdoors in a natural setting. This led to the creation of city parks dominated by lawn, a type of urban green space that remains popular to this day. Many city parks are essentially English landscape gardens minus the manor or castle.

In the New World

Toronto’s Spadina House, with its expansive lawn, represents the suburban home of a Victorian-era upper-middle-class family. Photo: City of Toronto

The most affluent North Americans have always followed European fashions attentively, and, especially from the 1870s on, their homes too began to be surrounded by lawn, first in the countryside, but soon just outside of towns as well. This is the birth of the suburb, then as now dominated by lawns. Where North Americans innovated was in setting the suburban house not near the street, which was the tradition for middle-class homes in Europe, but in the center of the lot, well back from the road, and surrounding it with lawn to clearly show the status of the owners.

Until this point, lawns were composed of whatever grew there naturally and could support mowing: not just grasses, but clover, plantain, dandelions and other herbaceous plants. There was as yet no concept of a lawn weed. Soon, though, grass and clover lawn seed mixtures began to be sold, not for pasture development, as in the past, but to create more beautiful lawns. Then the turf industry was launched, allowing homeowners to create instant lawns with rolls of turf. 

The affordable mower greatly stimulated the growth of suburban lawns. Photo: http://www.thriftyfun.com

With the arrival of cheap mowers, accessible cars and the 40-hour work week just before WWII, giving everyone a Saturday off to mow the lawn (Sunday, of course, being entirely devoted to religious activities), the middle class was ready to leave the city and settle massively in the suburbs, an area that had, until then, been reserved for the rich. And every little house had to be surrounded by lawn. In fact, lawns were not only a fad, but often municipal regulations actually required homeowners to plant a lawn … and some cities still do to this day.

Grass Takes Over

As mentioned, the first lawns were made up of any plant capable of surviving regular mowing, but that would change after the Second World War.

The golf green, with its incredibly short-mown grasses, became seen as the ideal lawn. Photo: http://www.hippostcard.com

At this time, golf was also gaining ground and although not everyone yet had the means to play this elite sport, envious homeowners did take note of meticulously maintained golf greens from which any plant other than grass was banned … and they wanted the same. So, when selective herbicides that could kill all plants in a lawn except grasses hit the market after World War II, they were instantly popular. No one questioned their safety. As long as they gave better lawns, that aspect was swept under the carpet.

Clover, until then considered part and parcel of a healthy lawn, now had to be banned as a “weed”. From the 1950s to the 2000s, a good lawn was a grass lawn. Nothing else was tolerated.

The Lawn Today

Quite frankly, not that much has changed since the democratization of the lawn in the 1950s other than suburbs becoming even more expansive. When, early in the 21st century, most countries banned cosmetic lawn pesticides for ecological and health reasons, many homeowners managed to circumvent the law by stocking up on now illegal herbicides or finding new ones that hadn’t yet been banned, thus continuing to poison the air, soil and waterways in their quest for the perfect lawn.

Despite that, attitudes are gradually changing. If you let too many dandelions bloom, you are still looked at askance, as in the 1950s. But what is different now is that, if there are no dandelions at all, you are now suspected of poisoning the environment and the reaction is hardly better. In fact, in some landscaping competitions, if your lawn is totally weed-free, it’s presumed herbicides were used and points are actually deducted!

Ecological lawn mixing clover and lawn grass. Photo: permies.com

A more sustainable lawn, where grasses and non-grasses are allowed to mingle freely, is catching on bit by bit, as home gardeners learn to use slower growing grasses that need mowing less frequently (low maintenance grasses), avoid lawn pesticides and herbicides, stop fertilizing other than grasscycling and let lawns slip into summer dormancy in areas where summer rains are infrequent. You also see more and more vegetable gardens replacing lawns in front yards and also far more interest in edible landscapes. It’s as if we are now proud to show that we grow our own vegetables rather than being ashamed of the practice.

A few dandelions just make the lawn more interesting. Photo: newcastlerecord.com

Still, I believe that the lawn will be a part of our peri-urban landscape for a very long time to come, but I do hope it will continue to take on a more and more natural look. After all, what’s so bad about having a few yellow flowers in a green carpet?

Uncover Cuttings Gradually

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Polka dot plants will wilt if exposed suddenly to dry air. Photo: nbolmer, houzz.com

Question: I was taking cuttings of a polka dot plant and covered it with a clear plastic bag because this was the only way it seemed to work for me. If I didn’t use a bag, the plant died. However, now when I try and remove the bag, the leaves of the plant shrivel and droop. Any ideas for what I can do?

Rowan

Answer: Yes, the polka dot plant (Hypoestes phyllostachya) is a delicate plant and has a hard time tolerating dry air.

The nerve plant is no happier in dry air. Photo: KonaKobenahvn, reddit.com

Another plant in the same category is its cousin, the nerve plant (Fittonia albivenis, formerly F. argyroneura and F. verschaffeltii).

Both need high atmospheric humidity in order to root, which is why you’d had success starting it inside a plastic bag. That creates “greenhouse conditions” where the humidity can be close to 100%. 

Remove the bag gradually so the plant can acclimatize. Ill.: celesteclark.com & laidback gardener.com

The secret to getting your now rooted polka dot plant to survive outside of the bag is to acclimatize it gradually to normal air humidity. One you’re sure it has rooted (you’ll be able to tell, because new leaves will start to appear), open the bag just a crack for a few days, then wider for a few days, then start pulling it down gradually, each time giving the plant a few days to adapt to the drier outside air. Eventually, your plant will be fully exposed and ready to face the drier air around it.

This technique is valuable too for most plants rooted under greenhouse conditions (high humidity). It’s always best to expose them gradually to outside air.

Remember, too, to water your polka dot plant regularly, keeping it at least slightly moist at all times. It doesn’t like dry soil either!

Winter Care

You may need to overwinter your polka dot plant under high humidity as well, such as inside a terrarium. Photo: Mary Kalanges

That said, depending on how dry the air in your home is, you may need to rebag or place your polka dot plant in a terrarium for the winter. The winter air in many residences is extremely dry, literally “desert dry”, often with less than 15% relative humidity (that in the Sahara Desert is usually about 25%).

Polka dot plants, nerve plants and other thin-leaved houseplants won’t be able to tolerate that. They need at least 50% humidity at all times and really prefer 70% humidity. A spot inside a clear plastic bag, under a transparent dome or in a terrarium may be the only places they’ll be able to survive the winter heating season.

If you try this, remember you’ll again have to acclimatize them, gradually, to outside conditions every spring when you remove their protective covering.

Bonus Plants

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Sometimes plants hitch a ride with others, so keep your eyes open! Ill.: http://www.pikpng.com & www.vhv.rs, montage: laidbackgardener.blog

I don’t know about you, but when I go plant shopping (and, to be honest, it’s about the only kind of shopping I enjoy … well, except for buying gardening books!), I’m always on the lookout for bonus plants. That’s what I call those extra plants you sometimes find in a pot.

Now, most often these are just another copy of the original plant. Say, in a row of echinaceas or delphiniums, most with just one plant in the center of the pot, every now and then there is a pot with two plants! I can see other gardeners mostly choosing the ones in bloom, but blooming plants generally tend to get broken when they’re handled or planted and I usually pass them up. I prefer getting two somewhat smaller plants for the price of one. I figure I’ve just bought the plant half price! 

Stowaway Plants

Bonus plants aren’t always just doubles of the original. Sometimes, something else is growing in the original pot, usually something much younger and clearly different from the original. A seedling of … who knows what? It could, of course, turn out to be a weed, but unless I recognize it as such, I really can’t resist trying. These are the ones I call stowaway plants. 

I confess: I was once taken in by a stinging nettle… but most of my stowaway plants have been plants worth growing. Photo: cambridge-news.co.uk

I have gotten some duds that way, true enough, and once tenderly cared for a stinging nettle for quite a while before it stung me and I realized what it was. But I’ve also discovered some truly stupendous plants hitchhiking in other pots. 

Ferns often seem to germinate in other pots and I’ve picked up some beauties that way. 

Armenian cranesbill (Geranium psilostemon), originally a stowaway, is now one of my favorite perennials. Photo: picfair.com

And my all-time favorite geranium, Armenian cranesbill (Geranium psilostemon), a giant of a geranium that blooms right through the summer into fall with startling dark-eyed brilliant magenta flowers, first came to me as a stowaway. It took me years to find out what it was, as it is just not on offer in nurseries where I live. True, it does self-sow quite abundantly, but I just love it. With plants of it now growing here and there throughout my yard, it now pretty much defines my summer garden.

I’ve picked some charming phloxes, sweet Williams, columbines and bellflowers that way, and also my very first Joe-Pye weed (Eupatorium maculatum… I think!). And even baby trees and shrubs, not all of which I’ve been able to keep because of space restrictions. And I mustn’t forget houseplants: they often have some pretty exciting stowaways. 

Plants Only

Mealybugs are the kind of stowaways you don’t want! Photo: askwetandforget.com

I should point out that I limit my choice of stowaways to plants. I also check plants for insects and if I find any stowaways in that category, unless I know it is something beneficial like a lacewing or a ladybug, the plant will remain in the store. In fact, if the bug is something truly horrifying, like mealybugs or scale insects, I’m very unlikely to buy anything in that outlet.

Bonus plants: just another thing about gardening that makes it so exciting!

Should You Use Algicide in a Bird Bath?

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Photo: http://www.birdspot.co.uk

Question: I have a bird bath in my garden that tends to turn quite green with algae. I’ve been cleaning it by hand, but wondered if I could use algicide from my swimming pool to keep it clean.

Dave Imbeault

Answer: It’s best not to use algicides or indeed any pool chemical in a bird bath. Most of them are at least slightly toxic to birds and you don’t want to poison your feathered friends. 

There are commercial products that are designed to keep birdbaths clean like “Songbird Essentials Bird Bath Protector”, “Fountain Fresh” or “Micro-Lift”. All do claim to be non-toxic and say they are enzyme-based, but apparently the product content is proprietary, so it’s far from clear exactly what “bio-enzyme” they contain. Still, many people do find it seems to work.

That said, regularly cleaning a bird bath is something you should be doing anyway, not only because of algae, but because birds are messy creatures and readily defecate just about everywhere, including in bird baths. That means the water can become quite contaminated even before algae show up.

Also, debris (fallen leaves, seeds, dust, feathers) slowly builds up as well and helps feed both bacteria and algae.

Also note that the cleanliness of the water of bird baths is doubly important, because the birds not only bathe in the birdbaths, they drink there too, so the risk of transmitting diseases increases when the water is not clean.

Add to that the risk of mosquitoes laying their eggs in the water, especially when it’s “been around for a while”. Mosquitoes are a possible reservoir for West Nile and Zika viruses. Regularly changing the water will eliminate that risk. (Adding a fountain to the bird bath will also help keep mosquitoes away: they don’t like moving water.)

The How-To

Vinegar and water are all you need to clean a bird bath … but you really should wear rubber gloves! Photo: thebirdfoodstore.com

So, if the bird bath seems fairly clean, just swish it out at least weekly with the garden hose; daily in really hot weather. This changes the water and removes most debris and bacteria.

Also, give the bath a more thorough cleaning at least once a month. Wearing rubber gloves, dump out the old water and clean with a scrub brush, using with nine parts fresh water and one part vinegar. (The National Audubon Society recommends not using soap or other cleansers, as they can strip the essential oils off bird feathers.) Scrub the basin, lip, and any spot where the birds land, perch, drink or bathe. Then rinse thoroughly with running water and fill again.

Just that bit of regular upkeep should keep algae away … and your birds happy! 

Confusion Over Hardiness Zones

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‘Sensation’ (Syringa vulgaris ‘Sensation’) is actually a very hardy lilac, fully capable of growing in hardiness zone 5. Photo: platthillnursery.com

Question: I just bought a ‘Sensation’ lilac, but I forgot to look at the hardiness zone. So here I am with a lilac from zone 3 while I live in zone 5. What will happen? Did I just throw money out the window? Which lilac is more suitable for zone 5?

Annie Bilodeau

Answer: You’ve misunderstood how hardiness zones work.

When some nurseries put only one hardiness zone on a plant label, in this case, zone 3, that was not meant to exclude all the other zones. You’re supposed to understand that the zone given is the coldest one the plant can support, but the plant will also grow in warmer zones. It is the minimum zone the plant can tolerate.

In the case of your lilac, it’s capable to tolerating quite serious cold, down to -40ºF/-40ºC, but will also do fine in milder climates, like your zone 5, where winter temperatures are much warmer. Check the table to better understand.

Now, this confusion would have been avoided if the label provider had given the range of hardiness zones the plant is adapted to … and many nurseries do. In the case of your ‘Sensation’ lilac, for example, as a cultivar of the common lilac (Syringa vulgaris), that would be zones 3 to 7 (common lilacs need a cold winter and won’t readily bloom in milder climates, that is zone 8 and up). As you can see, zone 5 is safely ensconced in the middle of the lilac’s cold tolerance range.

So, when you shop plants and see only one zone on the label, keep in mind that you can buy plants from your hardiness zone (5), but also plants tolerant of greater cold (zones 1 to 4 in your case). So, 1, 2, 3, 4 and 5 are the ones you can choose. It’s those from zones warmer than your own (6 to 13) you need to avoid, as they won’t tolerate the colder winters in your area.

💡Helpful Hint: If ever you’re not sure of whether a plant is hardy where you live, why not ask someone from the nursery staff? They’ll be able to direct you to plants that will grow well in your area. 

To answer your second question, “Which lilac is more suitable for zone 5?”, almost all lilacs are hardy in zone 5, so you could pretty much take your pick.

Accidental Invader May Stop Europe from Sneezing

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Distribution of ragweed pollen in Europe just before the arrival of the ragweed beetle. Ill.: European Aeroallergen Network

Europe has been under the attack of common ragweed (Ambrosia artemisiifolia), accidentally introduced from North America, for a century now and it has spread substantially, especially over the last two decades, to the point where it is now present nearly everywhere in Europe and indeed in Asia as well. 

The flowers of common ragweed (Ambrosia artemisiifolia) are the main cause of late season hay fever. Photo: newcastlebeach.org

The airborne pollen of this North American plant is the main cause of late season hay fever, a new disease for Europe, but one from which some 13.5 million Europeans already suffer, causing not only a lot of human discomfort, but costing health-care systems billions of euros each year.

But after watching the pollen rate rise constantly, year after year, Italian authorities were surprised to see it drop radically in 2013 near Milan’s international airport. An investigation showed that ragweed plants there were being devoured by a small beetle, reducing its flowering to nearly zero and thus causing ragweed-induced allergies to drop to barely perceptible levels. 

Ragweed defoliated by ragweed beetles and their larvae. Photo: Peter Toth, internationalragweedsociety.org

The culprit was soon identified as a North American interloper, the ragweed leaf beetle (Ophraella communa). It had apparently traveled to Italy by plane on baggage or merchandise, then escaped into the wild near the airport. 

Interestingly, the beetle was already being studied in Europe as a possible means of biological ragweed control, but authorities had been hesitant to release it, concerned it might attack sunflower plantations or other crops, as it’s possible to induce it to consume sunflower leaves in a laboratory setting. 

The accidental release let the horse out of the barn, though. Soon it began to spread throughout Northern Italy, affecting 100% of ragweed plants in some areas … and as it did, airborne pollen levels dropped to by up to 82%.

It turns out that this beetle is not at all interested in sunflowers in real life (whew!), but rather consumes only ragweed. 

The ragweed leaf beetle was also accidentally released in Japan in the 1990s and it is now widespread and successfully reducing pollen levels. It likewise showed up and is thriving in China. In Europe, it is for the moment found mostly in northern Italy and nearby Switzerland and has recently been discovered in Croatia. Authorities are analyzing the situation before introducing it to other areas. 

The beetle is especially efficient in warmer climates, such as Italy, where there are 4 generations per year. It might not be as efficacious in colder climates where there may be only one generation per year.

Insignificant-Looking, but Abundant

Adult ragweed beetle (Ophraella communa). Photo: inaturalist.ca

The ragweed leaf beetle is a small, innocuous-looking beetle about 3.5 to 4 millimeters long, brownish or yellowish with dark brown stripes and dark brown antennae.

Ragweed beetle larvae. Photo: Yurika Alexander, bugguide.net

Its larvae are yellowish to grayish and look a bit like pillbugs.

Beetle eggs. Photo: Heinz Müller-Schärer, internationalragweedsociety.org

Females lay clusters of orange eggs under ragweed leaves; when the nymphs hatch, they defoliate the original plant, then pupate for a short period. When they emerge as winged adults, they disperse to other ragweed plants. By the time the fourth generation of beetles has eaten its fill, the plants are so damaged they no longer produce flowers. 

The other ragweed leaf beetle (Zygogramma suturalis). Photo: Judy Gallagher, Wikimedia Commons

The ragweed leaf beetle was also released, purposely, in China to control a similar problem and with equal success. A different North American ragweed leaf beetle (Zygogramma suturalis), with three broad deep brown stripes on a yellow background, has been released in Russia, also dealing with a ragweed problem, with great success so far. 

Why Not in North America?

Given the huge success so far of ragweed control by the two ragweed beetles in countries to which they have been introduced, the question that begs to be answered is … why are these insects not keeping ragweed under control in their native North America? 

Ragweed remains abundant in North America, in spite of the presence of ragweed beetles. Photo: http://www.illinoiswildflowers.info

One or the other of these ragweed beetles (and other species) are found throughout the United States, southern Canada and northern Mexico, roughly covering the entire range of common ragweed, yet ragweed allergy remains a serious problem there, affecting about 49 million people and costing billions of dollars each year in medications and lost wages. The beetles have therefore been present for thousands of years. Why are they not obliterating ragweed in its home territory?

The answer is likely because something is limiting their predation.

Remember, these beetles have no natural predators in Europe and Asia and therefore the only thing that could stop their proliferation would be a crash in the ragweed population. (Since ragweed seeds can geminate up to 40 years after they were produced, that might take a long time!)

In North America, there are likely dozens of predators and parasites of ragweed beetles, from diseases to insects (ladybugs, lacewings, etc.). And even local birds probably see them as an excellent food source. Also, the beetles produce fewer generations in the northern part of their range, so consume fewer leaves there. As a result of all these factors, beetle populations in North America tend to cause only limited damage to ragweed, not enough to prevent them from flowering … and if ragweed flowers, it will release its pollen: about a million grains per plant every single day! 

Ragweed beetles being raised for mass release. Photo: P. Tóth, onlinelibrary.wiley.com

One idea that is under consideration is the mass rearing and subsequent release of one or the other of the ragweed beetles in order to allow it to outcompete its predators and overcome climactic limitations. This is already being done in China and I’m sure ragweed sufferers would welcome it in North America as well.

A future without ragweed pollen filling the air? I for one look forward to it, as I’m a ragweed sufferer myself.

Lavatera No More

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Lavatera × clementii ‘Rosea’ is now Malva × clementii ‘Rosea’. Photo: gardenersdream.co.uk

Yes, the genus Lavatera is gone, taxonomically speaking at least, and its species have been transferred to Malva, commonly called mallow. Genetic and morphological studies published in 1998 by botanist Martin Forbes Ray show that the two genera showed so many common characteristics there was no reason to separate them. 

The combined genus now contains some 50 species, including annuals, biennials, perennials and soft-wooded shrubs.

A Gardener’s Reaction

Malva moschata (left), the former Lavatera thuringiaca (right). Not much of a difference, is there? At least, not in the flowers. Photo: plants.alsipnursery.com & Nordelch, Wikimedia Commons

In a sense, this will be a relief to gardeners like me who’ve always had a hard time telling lavateras (Lavatera spp.) from mallows (Malva spp.). In fact, most of us have always called Lavatera species mallows anyway, or possibly tree mallows if we were trying to make a distinction between the two. 

However, Linnaeus, who originally separated Lavatera from Malva, was big on floral parts as a means of identifying plants and came up with the following means of distinguishing between the two: in Lavatera, the epicalyces (an additional row of floral parts below the sepals) are fused together at their base, while in Malva they’re free (not fused together), although they may be fused to the sepals. What? I mean, did you even understand that? At best, you’d have to turn the flower over to distinguish the two. 

Today, though, DNA is considered more valuable than flower bits, resulting in many changes in horticultural nomenclature … as with incorporating Lavatera species into the genus Malva.

Denial or Acceptance?

But I’ll have to change my plant labels! Ill.: Chelsea O’Byrne, http://www.theglobeandmail.com

This name change is only being very reluctantly applied in the horticultural world (nursery people generally don’t like it when plant names change!), so most sources either still use Lavatera alone, while others still list Lavatera, but mention the genus change in their plant descriptions. Even Wikipedia has only recently started to acknowledge it. The statement “All species previously placed in Lavatera have now been transferred to the related genus Malva” now appears on the Wikipedia Lavatera page with a similar mention on the Malva page. But there is still a Lavatera page.

For most species, only the genus name changes, so, for example Lavatera thuringiaca simply becomes Malva thuringiaca, so there really isn’t much to remember. Especially since the average gardener has always called lavateras by the name mallow anyway.

The annual mallow, formerly Lavatera trimestris, is now Malva trimestris. Photo: http://www.vanmeuwen.com

Here some of the better-known species with their new names:

  • Malva cachemeriana (formerly Lavatera cachemeriana).
  • Malva × clementii (formerly Lavatera × clementii).
  • Malva maritima (formerly Lavatera maritima).
  • Malva olbia (formerly Lavatera olbia).
  • Malva thuringiaca (formerly Lavatera thuringiaca).
  • Malva trimestris (formerly Lavatera trimestris).

So, change your labels … or don’t. But I think the gardening world will slowly come to accept this change. It’s such an obvious one!

Grasshoppers in the Garden

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Grasshoppers show up in just about every garden. Photo: http://www.capjournal.com

They’re here, they’re there, they’re everywhere! Yes, grasshoppers do get around. There are some 11,000 species and they’re found all over the world except Antarctica and a few isolated islands. 

Grasshoppers are mostly ground-dwelling insects with strong hind legs that allow them to escape from their enemies by jumping. Although they can also fly, they usually do so only over short distances. And they are almost all herbivorous: i.e. they’re plant eaters. Therefore, they’re not a group of insects the average gardener is going to love.

The very simple life cycle of the grasshopper. Ill.: microcollegium.canalblog.com

From the time they hatch, usually in spring, they already resemble their parents, but in miniature, then grow by stages over the spring and summer to their full size. The bigger they are, the more they eat! In most climates, they only stop eating when frost kills them.

As they grow, their original food supply (often some sort of grass) begins to be overharvested and competition among them increases. That’s when they tend to start to leave their favorite haunts, fields and meadows, and move into gardens. In fact, some species they increase so much in numbers they form swarms and are then called locusts.

But I need to give grasshoppers their due: they’re a major food supply for birds, lizards, ground beetles, spiders and others, so are beneficial to the environment. And their excrement makes great plant fertilizer. Also, when they’re only present in small numbers, they do little serious damage to our gardens. 

Chewed leaves could have a lot of causes, but when grasshoppers are present, they’re the likely culprits! Photo: bugspray.com

Of course, when those numbers increase and you start to see chewed leaves and ragged holes, plus similar damage to stems and fruits, they’ll no longer seem so environmentally friendly. They’ve been known to wipe out entire crops, although more so in farmers’ fields than home gardens.

When Grasshoppers Go Overboard

Grasshopper problems in home gardens tend to be mostly outside of cities. Typically, the garden is surrounded by agricultural fields, meadows or natural grassland and at a certain point, usually in midsummer and especially in years of drought, they leave the fields and migrate to your carefully tended plants. 

They do have distinct preferences: first and foremost, grasses and cereals, including corn, wheat, rye, barley and rice, plus alfalfa and soybeans. When those are in short supply, they switch to other plants, including clover, lettuce, beans, carrots and onions. While they aren’t too fond of squash, peas and tomatoes, when they’re starving, there isn’t much they won’t eat, even attacking trees and shrubs.

What to Do When Grasshoppers Attack

Most grasshoppers are green or brown. They often change color as they mature. Photo: http://www.mtpr.org

Grasshoppers are very hard to control, so, at best, you can only expect moderate success.

Here are some methods of limiting their damage:

Keep nearby fields well watered. Well, you can only do that if they’re your fields, but grasshoppers will have no need to move into gardens if fields nearby are nice and lush. 

Try biological controls. Again, you have to be the owner of the fields where the grasshoppers spend their youth, but you can spread a fungus (Nosema locustae) over fields where they occur. When ingested, it causes them to stop feeding and eventually die. It’s most effective on young grasshoppers. Nolo Bait and Semaspore are two products containing this fungus. Another such fungus is white muscadine disease (Beauveria bassiana), sold as BioCeres WP, Myotrol and under other names. Other biological controls (bacteria, viruses, predatory flies and wasps, etc. are also being studied and may eventually become available.

Don’t expect to see these products in garden centers! They’re usually only available online from companies specializing in biological controls.

Place a perch here and there for kestrels: they love grasshoppers. Photo: 200723D Peter Brannon, Flickr

Encourage their enemies. Do everything you can to attract birds to your garden (feeding stations, nesting boxes, bird baths, etc.). Even otherwise unappreciated birds like starlings, house sparrows and grackles are great predators of immature grasshoppers. Grasshopper sparrows, horned larks and kestrels love the adults. Free-range chicken, ducks, turkeys and guinea fowl are superb hunters of grasshoppers at all stages of their life, from egg to mature adult. 

As mentioned, ground beetles, spiders and praying mantises are also among the grasshoppers’ predators. You can release praying mantises, for example, and thus increase their numbers. Do note, though, if you have fowl running loose, they’ll eat all of the above.

All sorts of grasshopper-controlling microbes and parasites (bacteria, fungus, viruses, etc.) live in undisturbed soil, so no-till gardening can be helpful to a certain degree.

Treat with Pesticides. Most of the pesticides a farmer would use against grasshoppers, like carbaryl, malathion and acephate, are either not available to home gardeners or not something you would want use in a home garden, notably one where you grow vegetables. Permethrin is possibly more acceptable, being less persistent, while neem, diatomaceous earth, kaolin clay, insecticidal soap and hot pepper wax are organic and fairly effective if used at the right times. Some gardeners swear by garlic spray as a grasshopper repellent while others have no luck with it. 

Keep weeds down. Many weeds are favorite grasshopper foods, so removing them will make your garden less attractive to grasshoppers.

Put in a grass hedge. Surrounding your garden with tall grasses—and keeping them well watered!—can be helpful, as they’ll keep grasshoppers occupied.

Floating row cover. Photo: Lee Valley Tools

Use floating row cover. Protect specific crops with floating row cover. You don’t usually need to support this kind of row cover: as the name suggests, it’s supposed to “float” overtop the plants, resting on their upper leaves. However, where foliage touches the fabric, grasshoppers have been known to gnaw their way through to reach it, so raise it above the plants on hoops and stakes. Or try impossible-to-chew aluminum screening.

Grow Plants Grasshoppers Don’t Like. All the above methods are fine in areas where grasshoppers are just an occasional annoyance, but where they’re a serious problem every year, the only logical solution is to switch to plants they don’t like. 

Since there are many species of grasshopper and each will have its preferences, plants they don’t like will likely vary from one region to another. You’ll soon start to learn on your own which plants they tend to ignore under your conditions. However, the following plants are said to be ones grasshoppers will generally avoid, so you might want to start with them: 

  • Artemisia
  • Calendula
  • Cilantro/coriander
  • Crepe myrtle
  • Forsythia
  • Jasmine
  • Juniper
  • Lilac
  • Moss rose (Portulaca)
  • Pea
  • Pink (Dianthus)
  • Sage
  • Salvia
  • Squash
  • Tomato
  • Verbena

For most gardeners, grasshoppers are only going to be an occasional problem, but those who have a recurrent problem with them have their work cut out for them. They are really very hard to control!