Moths often pollinate the same flowers as bees, but at night. Photo: Aditidutttyagi10, Wikimedia Commons
One side of the Lepidoptera family is made up of beautifully colored, dainty, diurnal butterflies that flit from flower to flower in our gardens and are universally loved. The other is composed mostly of nocturnal insects with dull brown, gray or off-white wings: moths, insects we scarcely notice and usually give short shrift to. But—surprise!—moths are actually turning out to be important pollinators … and do a better job at it than the average butterfly.
A joint study at the universities of York, Newcastle and Hull has found that moths have an important but frequently overlooked ecological role: when the bees, hoverflies and butterflies go to bed, moths take over as pollinators. Under cover of darkness, and thus generally unobserved, they often pollinate the same flowers, but carry the pollen over longer distances.
Elephant hawkmoth with orchid pollen stuck to its eyes. Photo: John Bebbington, phys.org
Pollen actually sticks better the average moth’s hairy body, making them more efficient pollinators than slippery-sided butterflies. The scientists in the study tested moths for pollen and found more than 35% of them carry it. Plus, over half the plant species whose pollen they carried were not previously known to be pollinated by moths. That includes both commercially important crops (peas, beans, rapeseed, etc.) and many, many native and ornamental plants. Also, there are more than 10 times more moth species than butterfly species, the potential of most of which has never even been considered, let alone thoroughly studied.
Not all moths are desirable, of course. First, some moths don’t even visit flowers: they have no mouth parts (though their larvae did) and spend their short adult lives seeking a mate, mating and laying eggs. Others have larvae that damage desirable plants (as do some butterfly larvae, by the way). The cutworm is a moth larva, for example, as is the corn earworm. And there is the universally abhorred clothes moth that attacks woollens, silk and other natural fibers. Most moths, however, turn out to be more helpful than harmful.
Knowing moths are generally beneficial, you can work on attracting pollinating species to your garden, much as you may have done with bees, hoverflies and butterflies. Among others, you can:
• Grow night-scented plants like flowering tobacco, datura and moonflower that attract moths from afar; • Grow white or pale-colored flowers (favorites with moths); • Leave out overripe fruit (bananas, pineapple, grapes, etc.) overnight; • Avoid spraying toxic pesticides;
And especially:
• Teach friends and family about the beneficial nature of moths. I’ll sure they’ll be surprised!
Moths: among your garden’s very best friends. Who knew?
Firefighter working to save the Wollemi pine. Photo: Sydney Morning Herald
The horrible brushfires racing through Australia in late 2019/early 2020 very nearly wiped out the last stand of an iconic tree: the Wollemi pine (Wollemia nobilis). However, government officials announced on January 15, 2020, that it had been saved in extremis by a team of firefighters on a secret government mission.
There are fewer than 200 trees left of this critically endangered species, all found in a single narrow gorge in a remote section of Wollemi National Park, New South Wales, some 150 km (93 miles) northwest of Sydney.
The plant has been fully protected ever since shortly after it was first discovered in 1994 by a team led by David Noble (the botanical name Wollemia nobilis honors both the park where it is found and its discoverer). Considered a living fossil, it can be traced back some 200 million years when similar species were abundant throughout Australia, New Zealand and Antarctica. The genus has been in decline over the last 40 million years until only this one last species in this one last stand was left.
Wollemi pine. Photo: gardenbreizh.org
The Wollemi pine is not a true pine (Pinus spp., from the family Pinaceae), but from an entirely different family of conifers: the Araucariaceae and is thus more closely related to the popular houseplant called Norfolk Island pine (Araucaria heterophylla). With its long, flat needles arranged in two to four flattened rows, it really looks nothing like any plant you’ve ever seen. It’s a multitrunked tree, reaching from 25 to 40 m (82 to 131 feet) in height, abundantly branching from dormant buds on its very rough and knobbly trunk.
Saving a Relic Species
Fire racing through New South Wales. Photo: news.com.au
To protect the tree in the wild, its location had been kept secret and only a handful of people were allowed to visit the site, always wearing protective clothing so as not to accidentally introduce any harmful insects or microbes. (This, after a scare in 2005 when a pathogen, Phytopthora cinnamomi, was observed in the native population, apparently brought in by unauthorized foot traffic.) However, when government officials realized the Gospers Mountain mega fire was racing towards the gorge shortly after Christmas in 2019, they sprang into action.
Saving the Wollemi pine. Video: Associated Press
Air tankers applied fire retardant to surrounding forest. Helicopters dropped firefighters into the gorge where they installed an irrigation system to increase the moisture content of the soil. All participants were sworn to absolute secrecy as to the exact location. Then they were taken out for their own safety.
For four days, there was so much smoke that no one knew whether the trees had survived. When the smoke finally cleared, though, it was clear that the stand was in fairly good shape, even though most of 5,000 km2 (1,900 sq. mile) Wollemi National Park is now little more than ash and rubble. Two trees are apparently dead, some sustained minor injury, but most are perfectly intact.
Now Grown Worldwide
Young Wollemi pine for sale. Photo: John Dalton, Wikimedia Commons
Even had the fire destroyed the last grove of Wollemi pines, that would not have been the end of the tree, as backup trees are now available. The Wollemi pine grows readily from cuttings and these have been shared with botanical gardens all over the world. Seed too has proved viable. In fact, some nurseries now offer seeds or trees to home gardeners, although the tree is still very rare and usually quite expensive. It turns out the Wollemi pine is actually easy to grow, adapted to full sun or, preferably, partial shade in moist, acidic soils, although not very hardy (USDA hardiness zones 9 to 11).
Little remains of the forest in Wollemi National Park. Photo: Sky News
Wollemi National Park now faces decades of slow recovery. Millions of trees and millions of animals have been lost. Australian forests are largely adapted to fire, which is part of their natural cycle in most areas, but increasing drought thought to be caused by climate change threatens their ability to recuperate. Let’s hope Australia can count on a few years of good rains to allow Ma Nature to do her job.
And wise gardeners should also take this as a warning that climate is real and we all have to change our habits.
I recently saw a very funny television commercial about Splenda Naturals brand Stevia called “The sweetest thing you COULD grow” (see below). I laughed pretty much all the way through.
The premise is that you could grow stevia yourself, but it’s such a bother when you could simply open a pack of Splenda stevia and pour it into your ice tea. One character says about growing stevia, “I mean, if you had time, and you liked gardening, and—you know—you liked kinda doin’ stuff the hard way.”
And it’s sooo true … except that gardeners do like gardening and they do like “kinda doin’ stuff the hard way.” Plus, growing stevia really isn’t that hard!
So, the commercial backfired with me. It simply made me want to grow stevia even more, thus thumbing my nose at big business. And besides, I already grow stevia and have for years.
Stevia may be a commercial sweetener these days, but it was originally a plant: Stevia rebaudiana, from the Asteraceae family. You may hear it called sweet leaf, sweet herb, honey leaf or candy leaf. It’s named after Pedro Jaime Esteve (1500–66), a Spanish physician and botanist, while the epithet rebaudiana comes from Dr. Ovid Rebaudi, the 19th-century Paraguayan chemist who first extracted the sweet constituents from the plant.
It hails from South America and has been used for some 1500 years by the Guarani people of Brazil and Paraguay who call it “ka’a he’ ẽ” (“sweet herb”). They use it to sweeten bitter foods and medicines and as a snack. It contains glycosides like stevioside and rebaudioside that repel insects (yes, the plant concocted them as natural insect repellants!), but fresh leaves also have 10 times the sweetness of sugar. (Commercial stevia concentrate can be 300 times sweeter than sugar!) Humans can taste the sweetness, but can’t digest the glycosides. And that means stevia is a natural sweetener with essentially no calories, which is why stevia is so often of interest to people wishing to reduce their caloric consumption.
The flowers are not very impressive. Photo: Forest and Kim Starr, Wikimedia Commons
The plant is a small shrub about 30 to 80 cm (1 to 2.5 feet) in height with oblong, mid-green, slightly hairy opposite leaves with prominent veins, a lightly toothed margin and a very short, sometimes absent petiole. It grows upright at first, but older stems, green at first, eventually turning woody, bend and wander if you don’t cut them back. Clusters of tiny white flowers are produced in the late fall or winter, as it is a short-day plant. They aren’t particularly attractive and it’s probably best to remove them.
Growing Stevia
Despite its subtropical origin, stevia is easily grown in temperate climates as an annual. Or indoors as an edible houseplant. And it basically needs only the same care you’d offer to just about anything else you’d grow.
Plant stevia plants outside in late spring when both the soil and the air have warmed up… about the same season you would plant out tomato or peppers. Place them in full sun to very light shade in good garden soil: well drained, evenly moist, with a pH ranging from acidic to alkaline (5 to 8), although a range of 6.7 to 7.2 is best. In other words, your vegetable or flower garden would probably be perfect, as would any potting soil.
Space the plants about 20 to 25 cm (8 to 10 inches) apart and keep them evenly moist. Mulching can help with that and you’ll likely need to water during times of drought. Container plants dry out faster than garden plants, so keep a special eye on them.
Whatever fertilizer or compost you apply to your other garden plants will suit stevia just fine. There is no need to fertilize abundantly: as with most herbs, the taste is more concentrated when the plant is a bit underfertilized.
Stevia is not frost hardy and will not survive outdoors in temperate climates. It will live on in USDA hardiness zones 9 and above, and sometimes even 8, as it will grow back from the base if only the leaves are frosted. Prolonged freezing, though, will kill it.
Indoors
Stevia grows readily indoors provided you offer it quite intense light. A sunny windowsill or a place under fluorescent or LED grow lights will suit it wonderfully.
Stevia can be bit etiolated and floppy in the winter, but it still survives. Photo: countrylivinginacariboovalley.com
In natural light, it will probably etiolate somewhat during the short, gray days of winter, but you can then simply prune it back. It will start to look better when a burgeoning spring brings more sun.
Watering is as for almost any houseplant: when the potting mix is dry to the touch, water thoroughly with tepid water. How often you need to water will depend on your growing conditions as well as the size of the pot (large plants in small pots will need more frequent watering).
Stevia wilts rapidly when its soil is dry, but will recuperate if you catch it before it goes too far. Still, letting it dry out with any frequency is not a good idea, as each drought session weakens the plant. In fact, underwatering is second-biggest cause (after lack of light) for failure with this plant.
It seems to be very resistant to insects and diseases, so no worries there.
Normal home temperatures are fine. Stevia prefers a fairly humid atmosphere, but will survive dry indoor air. Just about any fertilizer will do: apply it during the spring and summer months.
Repot annually, as the plant does spread through offsets and will eventually fill its pot. When you find yourself needing to water more than once a week, you can be sure your plant needs more root room.
Propagation
Stevia is not a long-lived plant and diminishes in quality after two or three years, after which time it’s best to start new ones.
Rooting stem cuttings is the easiest way of multiplying stevia. Photo: Stephen Nellas
And taking stem cuttings is probably the best way to go. This can be done at any season, but most gardeners will probably root stems from garden plants in early fall in order to bring young plants indoors for the winter. Apply a touch of rooting hormone to the cut stem and root the cuttings in ordinary potting mix kept slightly moist under clear plastic dome or inside a clear plastic bag. You can also root stevia in water, but then its long-term success rate is much lower.
Alternatively, you can also divide mature plants and pot up the divisions.
First, you probably won’t be able to grow stevia from seed you harvested yourself. Cross-pollination is necessary for the flowers to produce seeds, so you’d need two different clones … and most nurseries sell cutting-grown plants that are all identical. Also, in most climates, your plants will be indoors at blooming time (October through December in the Northern Hemisphere), so pollinating insects won’t reach them. Thus, seed production isn’t too likely.
Secondly, commercially produced seed, while sometimes available, is very hard to germinate. Stevia is probably in fact among the most difficult herbs to grow from seed. Try sowing the seeds on the surface of a damp, sterile seed mix. Press lightly, but don’t cover with mix. Do cover the tray with a clear plastic dome. Bottom heat is essential: use a heat mat. And expose the tray to light, also needed for germination.
Even under those conditions, expect only a minority of seeds to sprout.
So… I suggest reconsidering starting plants from seed: cuttings or division really are the ways to go.
You can harvest and use leaves at any time for fresh eating, but the taste is most concentrated in autumn, just before the plant blooms. If you are growing stevia with the intention of drying it (which concentrates the sweetness even more and makes it possible to store it), fall would be the logical season to do so.
The easiest way to harvest stevia is to cut off a few stems, leaving about 10 cm (4 inches) at the base so it can grow back, then strip off the leaves. The soft stem tip is also edible.
Using Stevia
Stevia can be used in almost any recipe that needs a touch of sugar. Photo: Lilgrandma likes, pinterest.ca
I’m more a gardener than a cook, so make only a limited use of stevia leaves. Most often, I eat it fresh, as a snack, often with my grandkids. I’ve told them it’s called “sweet leaf” and they really bought into that. I haven’t yet convinced them that it replaces dessert, but I’m working on it.
Of course, stevia can be used much more widely than that. It’s popular as a replacement for sugar in tea, coffee, lemonade and other drinks, you can sprinkle it on hot and cold cereals or add it to smoothies and yoghurt. It’s also used in baking of all kinds: 1 teaspoon of dried crushed Stevia leaves equals about 1 cup of sugar. However, you’ll have to seriously modify any favorite recipes, as stevia may replace sugar’s sweetness, but it can’t replace its volume and texture.
Besides being very sweet, stevia leaves do have a slight aftertaste, rather like licorice, a flavor that has been removed from commercial concentrates. Some cultivars with a reduced aftertaste, like ‘Sweetie Star’, are available. Check with a local herb grower for their recommendation.
As Splenda suggests, stevia is certainly “the sweetest thing you COULD grow,” but I disagree with the company in one regard: I think you SHOULD grow it. But still, thanks so much to Splenda for the amusing commercial!
Yes, today, January 25, 2020, is Seed Swap Day … and I just found out about it! You’d think someone would have told me (and perhaps someone did, but I failed to notice) so I could share the news with my readers. Well, as they say, it’s never too late to do the right thing, so I’m announcing it today.
The idea with Seed Swap Day is to take your surplus seeds and share them with other gardeners who also have surpluses. They could be seeds you bought, but where there were more seeds in the pack than you needed or seeds you harvested yourself of true-to-type (non-hybrid) seed varieties. They could be flower seeds or vegetable seeds.
Logo for National Seed Swap Day. Ill.: Kathy Jentz
Of course, the seeds have to be viable (most seeds stored under reasonable conditions are “good” for at least 3 years, some many more) and you have to know what they are (there are only so many “mystery seeds” most gardeners will want to deal with!) Also, you’d obviously want to note the name of the seed and details about it on an envelope.
But don’t we all have surplus seeds we could be sharing?
Seed Swap Day 2020
At a seed swap, you just lay out your seeds and take your pick from the others! Photo: Washington Gardener Magazine
This article is coming at the very last moment: sorry about that! So, this year, you’d have to call up a few gardening friends to get things started.
But maybe your garden club might like to organize something like this next year? Or your community garden?
Or maybe there is already a seed swap organized in your area?
In the Washington, DC area, for example, there is a big one every year: the Washington Gardener Seed Exchange, held in 2020 on Saturday, January 25, from 12:30 to 4:00 p.m. at Brookside Gardens in Wheaton, Maryland. They even have a program with speakers!
You can check on many of the seed swaps at the Seed Swap Day web site which offers a listing that is updated yearly. If you have a seed swap you want to announce, this is the place to go.
And there is also the Community Seed Network, set up to help facilitate the saving and sharing of seed, where you could “meet up” with others interested in sharing seeds. This could be the day you look into that.
History
Seed swap in Washington, DC. Photo: Washington Gardener Magazine
The first Seed Swap Day was organized by my friend and fellow garden communicator, Kathy Jentz, editor of Washington Gardener Magazine, on January 26, 2006, and it was so successful it has been repeated yearly. Soon Kathy had the day officially recognized as the National Seed Swap Day.
So, get out and do some seed exchanging today, put Seed Swap Day on your calendar app so it repeats yearly … and make sure to include a plan for a real seed swap day on your agenda for next year!
Do you remember how photosynthesis works from your biology class in high school? If not, here’s a quick revision.
In their green cells (chloroplasts), plants use the energy from sunlight, carbon dioxide (CO2) captured from the air and water absorbed from their roots to produce glucose they can later use for their growth and share, via their sap, with all their parts. Photosynthesis occurs during the day, while the sun shines. So, plants breathe in CO2 during the day through pores in the leaves called stomata and do all their photosynthesizing. They then carry out respiration at night, using the stored energy for growth and giving off oxygen and water vapor. Story closed.
Or is it?
Actually, some plants do their breathing at night, absorbing CO2 in the dark. Then they essentially “hold their breath” all day long, keeping their stomata closed. The CO2 they stored (in the form of malic acid) is then released for photosynthesis during the day, in the presence of sunlight. It would be the equivalent of a human being holding its breath all day and only breathing in the dark.
This remarkable aberration has been known for over 200 years, although it was only named in 1940. It’s called CAM: crassulacean acid metabolism or CAM photosynthesis. It was first discovered in plants from the crassula family, whence the name crassulacean.
Designed for Drought
CAM plants keep their stomata closed during the day; other plants keep them open. Ill.: plantcellbiology.masters.grkraj.org
CAM is essentially an adaptation to drought conditions. The typical green plant, with its stomata open during the day, releases about 97% of the water it absorbs into the air through evapotranspiration. Yes, all that moisture you so carefully applied through watering is lost to the air and contributes nothing to the plant’s growth. What a shocking waste!
CAM plants are much more efficient at water use. Because their stomata are completely closed during the heat of the day and only open during cool night hours, they lose much moisture to transpiration. They can therefore get along with much less water.
Desert and arid-climate plants are therefore often CAM plants, but so are epiphytic plants: those that grow on tree branches. Constantly exposed to moving, drying air, they need to hang on to their moisture to survive and CAM is a good way of doing so.
There is a price to pay for this, though: CAM photosynthesis is much less efficient than regular photosynthesis and plants that use it grow more slowly than normal plants. But at least it allows them to survive difficult conditions.
Convergent Evolution
All cactus and most succulents are CAM plants. Photo: pinterest.com
Although in some plant families, all the plants carry out CAM photosynthesis (the crassula family is one), CAM actually evolved independently many, many times in many different plant families. When plants grow under arid or epiphytic conditions, they develop different adaptations to that situation (a waxy coating, improved water storage capacity, more efficient roots, etc.) and many “learn” to do CAM photosynthesis.
Some 7% of all the world’s plants carry out CAM photosynthesis, including plants in over 300 genera and 40 plant families. Some do so exclusively. Others use regular photosynthesis under humid conditions and switch to CAM during periods of drought.
Among plant families where CAM photosynthesis is the rule is, as mentioned, the crassula family, but also the cactus family, both of which contain only CAM species. Both the bromeliad family and the orchid family have over 50% CAM species, which is not surprising, since most are epiphytes. But you even find CAM plants in such unlikely families as ferns (usually epiphytic ones) and cucurbits (the squash family).
Underwater CAM
Even a few aquatic plants (here Sagittaria) carry on CAM photosynthesis. Photo: http://www.amazon.com
Curiously, there are a few aquatic plants, like Sagittaria and Littorella, that have also adopted CAM. There’s obviously no problem about losing moisture through open stomata with these plants, but CO2 is less available in water (it diffuses 10,000 times more slowly than in air) and during the day, when most aquatic plants are photosynthesizing, competition for it is fierce. So, they switch to CAM photosynthesis to get a better share of a rare product.
Crassula acid metabolism: it’s not the photosynthesis they told you about in school, but some of the plants you grow probably use it.
With white walls, plants profit from abundant light. Photo: Le Sirenuse
Do you feel your houseplants aren’t getting enough light? Are they stunted, grow little and bloom less? Or do they produce long, pale, weak stems that bend towards the window (etiolation)? That means they’re starving for light.
If so, have you ever thought about painting the walls of the room white or at least a very pale color?
It may seem trivial, but the color of the walls, ceiling, floor and objects in the room makes a huge difference in the vigor of the plants that grow there.
Remember your physics class back in school. If black seems dark, it’s because it absorbs all the light rays that hit it. It is actually the absence of color. White, on the contrary, seems pale because it reflects all the rays. It is composed of all the colors. (By the way, plants appear green because they absorb all the rays that reach them except green.)
Plants need light for their survival: it’s their only source of energy. If dark walls or dark furniture absorb most of the light entering a room, the plants that grow there will capture less of it. On the contrary, in a room where white (or very light colors) dominates, a good part of the light is reflected back and forth until it is absorbed by the darker objects nearby by … such as plant foliage.
White Walls Turn Your Thumb Green
This is not a minor detail: the color of the walls makes a huge difference in how plants grow. In a room with pale walls (mirrors have the same effect), you can place plants well back from windows and they’ll do fine. In a room with dark walls, you’ll need to stick same plants right up against the window to get reasonable results.
I’ve been sharing this information for over 40 years and you have no idea the number of people who come to me to confirm that their thumb went from black to green (or vice versa) just because they painted their walls.
Even if houseplants are not your thing, if you’re a gardener, in just a few weeks you’ll probably start sowing vegetables and flowers for your garden. In that case, don’t forget that they too will greatly benefit from white or pale surroundings. Sometimes just a white panel placed behind the seedlings, so that sunlight bounces back towards them rather than diffusing into the room, completely changes their appearance … and your success rate!
Adapted from an article originally published on February 10, 2016.
Every seed is different. There are some 300,000 seed-bearing plant species (angiosperms and gymnosperms) on this planet and each one has seeds that are different from any other. In fact, sometimes similar-looking plant species are best told apart by studying their seeds.
As someone who has grown plants from seed for over fifty years, I’ve always been fascinated by seed shapes. Big ones, little ones, round ones, long ones, with sticky hooks or little parachutes: there’s just so much variety. I can recall as a lad opening a pack of mixed annual flowers and carefully separating the seeds by shape so I could see which each type would grow into. What a fascinating experience!
Match These Names to the Photos Below
Here are 20 common plants listed in alphabetical order. How many can you match with the photo below?
A. Apple (Malus domestica) B. Bachelor’s buttons (Centaurea cyanus) C. Bean (Phaseolus vulgaris) D. Calendula or pot marigold (Calendula officinalis) E. Castor bean (Ricinus communis) F. Clematis (Clematis sp.) G. Cosmos (Cosmos bipinnatus) H. Dandelion (Taraxacum officinale) I. Horse chestnut (Aesculus hippocastanum) J. Lotus (Nelumbo nucifera) K. Maple (Acer saccharinum) L. Milkweed (Asclepias syriacus) M. Nasturtium (Tropaeolum majus) N. Oak (Quercus rubra) O. Pelargonium or geranium (Pelargonium × hortorum) P. Poppy (Papaver somniferum) Q. Squash or pumpkin (Cucurbita pepo) R. Sunflower (Helianthus annuus) S. Tomato (Solanum lycopersicum) T. Wheat (Triticum aestivum)
D. Calendula or pot marigold (Calendula officinalis)
H. Dandelion (Taraxacum officinale)
B. Bachelor’s buttons (Centaurea cyanus)
R. Sunflower (Helianthus annuus)
L. Milkweed (Asclepias syriacus)
N. Oak (Quercus rubra)
O. Pelargonium or geranium (Pelargonium × hortorum)
E. Castor bean (Ricinus communis)
T. Wheat (Triticum aestivum)
K. Maple (Acer saccharinum)
J. Lotus (Nelumbo nucifera)
C. Bean (Phaseolus vulgaris)
M. Nasturtium (Tropaeolum majus)
I. Horse chestnut (Aesculus hippocastanum)
F. Clematis (Clematis sp.)
Q. Squash or pumpkin (Cucurbita pepo)
G. Cosmos (Cosmos bipinnatus)
A. Apple (Malus domestica)
P. Poppy (Papaver somniferum)
How Did You Do?
0–4 correct answers: You’re probably very much a beginner with seeds. Try sowing a garden this summer and you’ll do better next time.
5–10 correct answers: You’re a very observant person, although maybe not a seed gardener … yet. Start your own vegetables and flowers from seed this spring and you’ll learn a lot.
11–15 correct answers: You’ve been gardening for a while, haven’t you, as you certainly know your way around seeds! Congratulations.
16–20 correct answers: You’re obviously a seed wizard! Maybe you should be writing this blog!
