Tuesday, September 26, 2023
Monday, September 11, 2023
Don’t do it! It’s the worst place to grow plants. The soil is toxic and they’ll all die. If you have ever read or heard stories about walnut trees, especially black walnut which is common around here, that’s the gist of it. But is it true? This popular belief has been widely reported and quoted over the years, often from reliable sources.Consequently, gardeners abhorred the thought of a walnut tree growing anywhere near their gardens. Because the black walnut is prized and much sought after for its beautiful wood, there’re many who would say the trees are worth more dead than alive.
The theory is walnut trees produce a chemical that inhibits the growth of other plants — the term used is allelopathy. The chemical is juglone and is believed to be exuded by the roots of the tree making the soil toxic to many plants. Other parts of the tree, including the leaves, are also said to contain juglone and it’s long been the recommendation that wood chips from a walnut tree should not be used as mulch and the leaves should not be composted.
However, it’s since been revealed that juglone is not initially present in the living tissue of the tree, but a non-toxic precursor called hydrojuglone is and it’s only converted to juglone when in the soil. I’ve composted my share of leaves from black walnut and never had an issue using the compost in my garden.Supposedly, juglone doesn’t affect all plants. There are long lists available of those that can be grown beneath walnut trees and others that can’t. Tomatoes, it seems, can’t be grown beneath the tree, but onions can. The problem with these surprisingly long lists is they’re apparently based mainly on observation — what’s been seen to be growing well or not, but not necessarily taking into account other factors that can affect growth.
There have been few if any scientific studies that give solid evidence supporting all these plant recommendations and the same goes for the belief that growing anything beneath walnut trees is an actual problem.
The question is, where did this belief arise? We are fortunate in that someone has done the work to find out. Linda Chalker Scott, Associate Professor and Extension Horticulturist at Washington State University has only recently completed a review of all possible material related to the issue and published a fact sheet on it.
Chalker-Scott reveals that back in the 1920s, despite farmers growing crops successfully near walnut trees, the belief took hold. By 1948, the United States Department of Agriculture felt the need to issue a press release assuring the public that there was no need for concern and that the trees were harmless to other crops, but still the belief persisted. Then, in 1951, experimental field testing began and guess what — little to no adverse effects were evident.
Some laboratory testing was done using juglone directly on seeds and seedlings and there appeared to be negative effects, yet the results were inconsistent. As with any laboratory testing, it doesn’t necessarily relate to what occurs in nature. Chalker-Scott concludes that all the scientific evidence for black walnut allelopathy can be traced to two publications, one of which has been withdrawn and another that is non-existent.
So, what is going on under black walnut trees? Ignoring the myth, the answer is probably what goes on under all large trees. The roots of most trees mainly occupy the top couple of feet of the soil and spread far beyond the dripline. Light rain never reaches the ground beneath the canopy and consequently, the tree grabs all the moisture from the soil along with the nutrients. It’s always difficult to grow much under any large tree, although many gardeners have been successful.
As for tomatoes, it’s the one plant that’s said to be a good indicator of the allelopathic effect. They often fail to grow when planted beneath a black walnut tree, but then why would anyone try to grow tomatoes there? It’s about the worst place. Tomatoes need lots of water — none there. They also need good, rich soil — hardly likely. And what tomatoes really need is plenty of sunshine.
Good luck with that in the shade of any tree. Don’t do it.
Monday, September 4, 2023
Doug Tallamy, American
entomologist, ecologist and conservationist recommends that 70% of plants in a
garden should be native species to
provide a seasonal food source for larval caterpillars, which specific
bird species depend upon as they fledge their young. It’s
become a popular talking point over the last few years, especially on social
media. It’s a worthwhile goal, and I encourage anyone to follow this advice
should they wish to do so. He writes also on the importance of pollinating insects.
Much of the current concern about pollinators took off after a report from Germany showed a drastic reduction in insects there. This was picked up by the media and made for alarming headlines — dramatic events are more publishable. Yet unlike Europe where almost all land has been modified for human use, findings indicate that large-scale insect declines across North America remain an open question. There are few studies showing an overall decline, although this doesn’t mean there are not areas where this has occurred.
This raises questions for me about the situation in this area. Prior to a couple of hundred years ago, southern Ontario was heavily forested, then the forests were felled to make way for farmland and much of the natural landscape was lost. Urban growth followed, absorbing swaths of that farmland, then in the decades following World War II, all manner of pesticides became available. They were heavily used in agriculture, by municipalities, and by homeowners.
This was a time when green lawns ruled and to ensure they stayed that way, they were sprayed heavily with weedkillers — remember the tanker trucks that roamed neighbourhoods leaving a chemical smell in the air? Thankfully, that ended in 2008 with the Ontario pesticide act.
Prior to about thirty years ago, other than grass, homes might have had a small vegetable plot out back with room for a clothesline. In the front yard, most had only what was termed a foundation planting out front, three or four evergreens and limited selection of flowering plants. There were far fewer sources for plants compared to now when big box and grocery stores have become garden centres. Filling the front and back yard with rare and unusual plants would have been seen as radical. This began to change largely due to the Communities in Bloom program starting in 1998, which encouraged front yard plantings, and over the last twenty years interest in growing flowering plants has surged.
Growing vegetables, too, has become hugely popular. However, backyards are still largely a play area for kids and pets, although many trees and shrubs have been added where none grew before. People build gardens for many reasons, and in an urban environment it isn’t easy to recreate a natural ecosystem where plants and insects have developed a complex web of interrelationships, yet those who opted to plant flower gardens with a wide range of plants have done much to support pollinators. Non-native plants might not cater to all species of insects, but they can provide nectar rich flowers for generalist feeders, and native birds and insects will happily feed on both native and non-native plants. It’s the specialist feeders that are most in need of specific plants that support them, like the monarch butterfly that relies on milkweed.
Planting any kind of garden is a positive thing when one considers what is being done to the planet, especially so as climate change, pesticide use, and loss of greenbelt continue to threaten pollinating insects on a much bigger scale than a simple garden that has long provided habitat where non existed before. So yes, do avoid using invasive, exotic plants, and certainly add more native species to attract pollinators, even 70%, but don’t be afraid to grow what you love, providing it causes no harm to the environment — know your plants.
It is worth noting that in the US, where the movement is strongest, pesticide use by home gardeners is still permitted. Eighty-five types of pesticide outlawed in other countries are still allowed there.
Thursday, August 31, 2023
It must have been an exciting time for botanists when they were first exploring the rainforests and mountain valleys of the world. At every turn, they’d discover something that had only ever been seen by the Indigenous people of the area. Alas, I must stick to exploring my own garden, staying away when mosquitos are about, and retreating to air conditioning when it’s too hot to putter.
Yet I can sense a little of that excitement when a new plant in my garden finally flowers, and I didn’t have to trek through a distant rainforest to discover it. It’s usually something I found at a nursery or grew from seed, a plant that anyone could grow. But occasionally, purely by chance something unique appears, something so unusual few have seen it, something that can’t be reproduced, at least not outside a lab.
I have had plants with strange flowerheads, mostly ones deformed by fasciation. Grow enough plants and it will show up. I’ve seen it cause flattened spires on Veronica and contorted echinacea flowers. Fasciation can be due to a virus or bacteria, a genetic mutation, or simply damage to the plant. The exact cause is difficult to determine. Sometimes the appearance is unsightly, but it would be rare for the whole plant to be infected. Another cause of deformed flowers is a viral-like disease called Aster yellows. It happens thanks to an organism spread by a leaf hopper, and it's more likely to occur during cool, wet summers, certainly not this one.
These aren’t common, but then something truly unusual appears, a once in a lifetime event, at least in my lifetime. A few years ago, a calla lily threw up a beautiful work of art, a perfectly formed twin flower, joined at the stem. I do keep the same tubers from year to year and I hoped it would occur again, or in subsequent years, but it’s never happened, at least not yet. It so impressed a friend when she saw it, that it inspired her to incorporate the image into one of her works. It’s now represented in a painting by artist Elizabeth Dailey. She calls the acrylic painting Lily Lily and feels it represents everyone's duality, like the Roman god, Janus.
Another floral surprise has occurred twice on a waterlily in my pond, about three years ago and again this year; however, it’s not as rare as I first thought. The plant is a cultivar named Wanvisa, an award winner that won the best new water lily of the year in 2010. I’ve had it in my pond since 2013 where it flowers reliably every summer. It has lovely peachy-pink blooms with yellow speckles, and it has a reputation for occasionally reverting in places to the bright yellow of one of the parents. This can happen on hybrid plants. Sometimes it’s welcomed, or not when the breeder’s intention is to produce a reliable plant that blooms with consistent features.
This was acceptable with Wanvisa because it contributed to an exceptional plant. Mostly, the changes are slight variations in colour, but sometimes it results in a few pure yellow petals or parts of petals that contrast oddly with the rest of the flower. The first time this happened on mine I was fascinated. The reversion occurred perfectly across the centre of the flower, a true two tone. More recently the reversion hasn’t been so precise, but it is exciting to see. It could be considered a Chimera, a genetic change when the cells of distinct species are mixed.
If you discover an odd plant in your garden, value it as you may never see it again. Unique holes from chewing insects don’t count.
Wednesday, August 23, 2023
The zucchini harvest is in and it's a bumper crop. That's one use for them -- as bumpers. Hang them over the side of your boat or around your dock. Anything to get rid of the things. Me, I'm running out of ideas. They're taking over the backyard, the compost is overflowing, and the relatives are pretending not to be home when we visit. Lately I've taken to leaving them at the front of the house with a sign saying, FREE. Naturally, I always choose a different house -- preferably on the other side of the city.
What I don't understand is, I thought I'd got rid of all my zucchini by the end of August, but I found more last week and again I had to take a detour on the way to work. I thought I was getting the hang of it, leaving before daylight and stopping on a quiet street, but this time I'd only just heaved one out of the trunk when I spotted someone writing down my license number. I put the zucchini back and took off real fast. I ended up leaving them on an elevator at city hall. It was either there or on a bus leaving town.
Then it happened again. The other morning, I discovered three more in the garden -- monsters. I couldn't understand where they'd come from. After the last episode I'd made a point of ripping out anything that resembled a zucchini plant, and yet here were more hiding out under the tomatoes, almost hidden under the foliage. This was impossible; zucchini may grow fast, but they are lazy travellers: They certainly don't drag themselves thirty feet across the veggie patch to lurk under tomato plants. I had a sneaky suspicion these were alien zucchinis -- that is, not grown in my yard.
I figured someone was using my place as a zucchini dump, and I had a darn good idea who it was -- Shirl from down the street. Whenever I see her, she's walking around with a zucchini under each arm, and I overheard her at the garden centre a while back complaining that her place was overrun with them. She was blaming the folks there for selling her zucchini plants instead of cantaloupe. She gave me a real zucchini-shrinking look when I muttered something about it serving her right for not knowing the difference. I would have kept my mouth if I'd known she'd bear a grudge. It had to be Shirl.
Guess where I took those latest zucchinis -- right down to her place, but not until after dark. Although there was a full moon that night, I wasn't worried. I figured Shirl would be asleep because, like me, she's an early riser, always up early puttering around the yard. I simply walked confidently through the gate and down into her veggie patch. I planned to be in and out in a flash. I shoved the zucchinis in beside her others and was about to leave when I spotted a slug. It didn't matter that it was one of Shirl's slugs; I automatically squished it. Then I saw another, and another. Next thing you know, I'm so busy squishing slugs I forget about the time.
I was still there when a light came on and Shirl appeared on the deck. I realized where I was and made a dive for cover -- right into a tangle of raspberry canes. It was all I could do not to scream, but I did whine a bit, which was a mistake because she thought I was a cat. She hollered something nasty and began throwing rocks -- beaned me right in the head. I still have the bruise -- and a lot of scratches. I lay there for three hours waiting for her to go back to bed so that I could go home. And if that wasn't enough, next morning I discovered two more ^&^$% zucchini in my own garden.
That evening I almost bumped into Shirl as she was coming around the corner carrying a zucchini as usual. I had my little red wagon and was hauling the ones she'd left in my yard the previous night. As we passed, we both smiled and said hello. I don't know where she was headed, but it wasn't my yard because I'd bolted the gate and, as a deterrent, floodlit the veggie garden. I didn't go anywhere near her backyard; getting beaned once is enough, but her car was parked in the driveway -- locked, of course. Actually, it's not a car it's a huge 4x4 with real big wheels -- that's all I'm saying.
From the Diary of a Mad Gardener -- see Amazon
Monday, August 14, 2023
Friday, August 4, 2023
This is when I recall my favourite garden quote by Sally Carrighar, one I should inscribe on the fence as a reminder: “The important thing is to know this flower, look at its colour until its blueness becomes as real as a keynote of music”. To this I’d add a reminder to observe artful intricacy of design.
Most are daisy-like, some double, but one in particular always catches my eye thanks to the unique design of its petals. They radiate out in a perfect circle, each one resembling a tiny spoon. I stop, I look, I smile, then I shake my head at this miniature work of art. It’s just one of the reasons to “get” gardening.
Saturday, July 22, 2023
Friday, July 21, 2023
If you have any doubts about their hardiness, plant them against the house in full to part sun, but I have hundreds of witnesses who can confirm that mine grow just fine in the middle of the garden, and they all know the correct botanical name, should anyone ask.
It's a pleasure to share, to discuss plants, and to answer questions from so many garden lovers, like "What’s the name of that plant?" Why, I frequently replied, it's Anonomenthanum something or other.
Wednesday, July 19, 2023
Echoing through the online world are these words: “What’s eating my plant?” And with the question is usually an image of a leaf riddled with holes, a close-up of a seedling felled like a giant redwood, or tiny stems brutally severed.
There’s no shortage of culprits. Rabbits especially are a menace and the only thing that truly works is a fence around the yard or wire mesh around the plants. It needs to be a couple of feet high and turned outwards at the base in an L shape or buried a few inches. It won’t stop squirrels or chipmunks unless it covers the whole bed. There are countless other suggestions online, but none are guaranteed. Most popular recommendations are blood-meal, soaps, or other pungent things. Animals don’t like strange odours, but they adapt, and what may appear to work for a while doesn’t always last.
The blood-meal can be effective and some swear by it, however, like other deterrents it must be repeated after rain, and too much spread around will upset the nutrient balance in the soil and encourage leafy growth at the expense of flowers or fruit. There are a couple of commercial products, Bobbex and Plantskydd, used for winter protection of shrubs and trees from deer, are a deterrent elsewhere in the garden, although they shouldn’t be sprayed on vegetables. One suggestion to deter critters is to spread human hair about. I can tell, you, I’ve been losing hair in the garden for years without any effect.
Other than damage by chomping animals, most damage goes on at the level where Rick Moranis shrunk the kids. Sometimes evidence of the culprit is obvious, slimy trails left by slugs, or clusters of aphids clinging to new growth — blast aphids off with a hose daily until they’re gone.
From flea beetles to lily beetles and cut worms to earwigs, identifying the specific insect that’s causing damage is key. Holes in leaves will only tell you one that a pest has visited. Like no one in the office will admit to taking the last donut, by the time you spot the damage the pest may well have dined and dashed.Much damage occurs overnight and that’s the time to observe. You may need to patrol the garden after dark with a flashlight, but let your neighbours know if they’re the suspicious type or you might find yourself in the back of a police cruiser and ranting about bugs won’t get you out.
Once you have identified the pest, you can determine the best means to deal with it, either with a barrier of some form or an insecticidal soap spray. These sprays must contact the insect pest. Please note, they don’t work by blanket spraying the garden. There are far more good bugs than bad ones. When predator insects are wiped out, the bug you’re trying to eliminate thrives. And you’ll be harming valuable pollinators, including bees and butterflies.
Certainly, there are instances where insects will ravage a crop, and that is disappointing, but often the damage is limited or short term, like with the four-lined plant bug. Right now, leaf miners have been busy on my Swiss chard, a problem that can’t be resolved with any spray as they’re within the leaf. It’s visually unattractive, but the chard will soon outgrow the damage and I’ll remove the affected leaves. Growing plants that attract predatory insects on or near the vegetable garden will be helpful, and it’s just as important to know the beneficial insects as well as the baddies.
Are we out of batteries for the flashlight again?