Gardeners are used to having to make some modifications to garden plans due to unforeseen challenges, such as an unexpectedly late frost or sudden, usually short-term, change in weather patterns. But never have we experienced a heat wave as we did last June, an early summer blast of heat, accompanied by unusually dry conditions that had begun earlier in the spring.
Between January and May, the rainfall was 64 per cent of historical average; in June, 60 per cent, followed by July, 0.0025 per cent and August, 20 per cent. (information from climate.weather.gc.ca).
Record breaking high temperatures during the longest days of the year meant little chance for cooling off during the shorter nights. Subsequent heat waves through the summer further weakened plants affected by the initial heat wave.
There are always surprises in store when growing a garden, both in successes and failures. But the biggest surprise this year, so far, is how climate change has suddenly become a harsh, in-our-face reality that requires our attention and adaptation in all future plans.
This spring, my garden started relatively ordinarily enough—battling with squirrels over young plants and acting on plans to avoid cabbage moths and ward off morning glory. Critters destroyed early planting as they dug down to access their winter stashes of hazelnuts. Later, plantings of lettuce and slow-to-bolt varieties of cilantro all bolted in the rising temperature when only a few inches tall.
I planted cabbage seedlings and covered them with tunnels of row cover to protect them from cabbage moths. After checking a couple of times, they seemed to be doing very well. The row cover swelled up like Jiffy Pop popcorn ready to burst and I excitedly thought about the fine harvest for sauerkraut. To my shock and horror, removing the cover revealed a huge clump of morning glory and a few straggly remains of cabbages that moths had devoured.
In the greenhouse, along with all the other seeds, I started an army of Mexican marigolds to plant out to do battle against morning glory. The Mexican marigold’s roots contain a chemical which is a deterrent to morning glory and has seemed to have kept this irritatingly persistent weed somewhat at bay. It stayed along the fence, but the vines crawled along the ground seeking something to climb, marigolds included.
Mexican marigolds are supposed to grow between three to four feet tall. But, I think due to the summer heat, some are upwards of 10 feet tall, beautiful plants but have still yet to bloom.
I planted Blue Lake pole beans in mid June, as beans like warm soil and I guess they really liked the unseasonably intense heat. They grew in an awe-inspiring frenzy, yanked their trellis to the ground then climbed over piles of pots and unused garden supplies to reach up into the sturdier mountain ash tree, producing heavily in the process.
In the greenhouse, eggplants and pepper plants gasped and wilted; many plants died. The thermometer almost exploded. To mitigate against the heat, I installed an irrigation system to provide extra water and left the door open.
Raspberry leaves and its fruit fried on the canes. But as the temperature returned more towards normal, the plants shot up to heights I have never seen before and slumped into unsupported heaps. A second, huge harvest of fruit the size of loganberries began to form, which is still holding promise of producing much later into the fall.
Sun-loving lilies, roses and blueberries were especially resplendent this year, and plums were astonishingly abundant and delicious. But, after very few blossoms, the apple harvest was minimal, with unsightly fruit that was full of blight.
Being a lazy gardener did pay off for the tomatoes. Since I didn’t trim off excess foliage from surrounding plants to expose them to as much sun as possible, the tomatoes grew in the shade and ripened beautifully.
I reached out to Powell River Garden Club members for others’ observations of this very strange summer. A picture Terry Faubert sent in bears testament to how her rhododendrons loved the hot dry weather. Apparently, wasps did as well.
Another photo shows a tricky wasp nest discovered on a bush just as her son was about to prune off this branch.
Margaret Cooper wrote in to share her puzzling, out-of-the-ordinary experiences:
“We loved the summer sun but it made a challenge with keeping the garden watered,” said Margaret. “Oh, how I wished I had installed an irrigation system. But I didn’t, so it was run-run-run moving hoses and still it was hard to keep up with it.”
Margaret said some good things happened in her vegetable garden, and some puzzling lack of success, too.
“We had a wonderful crop of climbing beans and they are still giving; the lettuce bolted to seed pretty quickly once the heat wave came; cucumbers gave us quite a good crop,” she added. “We had, and still have, an excellent crop of tomatoes but there were some faults resulting from the unusual heat and the struggle to keep up the water, quite a lot of yellow shoulders and hard green cores, and a bit of blossom-end-rot, which I know is not due to calcium deficiency.”
Margaret also remarked on her biggest conundrum.
“We had remarkable failure with our squash plants, all kinds; one golden patty pan of them all gave us a small yield, but nothing else did,” said Margaret. “The plants grew quite vigorously, oh yeah, but not one butternut has set on the three plants despite a great display of flowers. One miserable little spaghetti squash.
“With the zucchini, there were none of those jokes at our house about remembering to lock your car doors to avoid waking up to a car full of these usually overly prolific veg. We couldn’t even make one zucchini bread. From three bushes we garnered only one fruit, and that was not truly healthy, but we still used it because we were getting desperate.”
Margaret said a new kind of spaghetti squash, chilacayote, was tried, five plants in all.
“These made a very impressive show of vines and leaves but altogether only three squash set and two of these are pitifully small; I am wondering if anyone else had such a singular lack of success with their squash family,” she added. “Was it just too hot at the crucial times? It certainly wasn't for lack of watering.”
Effects of heat and drought
Anne Thompson has been developing a raised bed garden over the last few years and described how the heat and drought affected her plants, and how she plans to adapt her future plans to mitigate climate change.
“Because of the cooler spring weather this year, I was later putting in a number of vegetables, even the ones that prefer the cool temperatures,” said Anne. “The delay allowed me to build six more lower (12-inch) raised beds in the back part of my yard. One is devoted to shade-loving vegetables and one is for partial shade. The vegetables in these two four-foot by 12-foot beds did very well in spite of the summer heat; the other four receive more sun exposure.”
Anne said water restrictions were a necessary curse for the gardener during the heatwave.
“Even with a rain barrel on each of my five downspouts, without much rain to refill them, except during the thunderstorm, they were used up quickly; one of my plans for the future is to buy more of the same rain barrels, which can be connected in series,” she added. “Some of my plants: vegetables, grains, legumes, fruits and flowers did better than others. The ones that didn’t take as kindly to the heat included two of my eight types of my warm-weather beans, Soldat de la Beauce, which died, and Jacob’s Cattle, which dried up a bit; Sam (my cherry tree), and my Issais (naked kiwi plants) lost all their immature fruit.
“Although sweet potatoes usually like drought, I found that I had to give them an occasional watering. My hanging basket plants will need to be looked at again for next year with an eye to heat tolerance and lower moisture requirements. Or, as a water conservation measure, I may not have hanging baskets at all.”
Anne said to plan for the future, she will look at what the global warming scientists say are the most likely weather scenarios, particularly for Pacific Northwest coastal areas.
“Heat, drought, wind and other identified factors will guide my seed purchases,” she added. “Where possible, I may get into saving seed for some vegetables as this will help to fine-tune the seeds to my microclimate, although, with climate change happening so rapidly, that may be futile.”
Elaine Sissons was watching a news article one evening that showed how raspberry crops in Abbotsford were being devastated by sunburn. One farmer said the only way to save the crop was to cover it, but how could they cover their vast crops?
The next morning she got up to find some of her raspberry plants just starting to look like what she had seen the night before on the television. So, armed with her new knowledge and reemay cloth, she was able to drape her small bed of raspberries and protect them from the sun.
“Yes, a few berries dried up, and some leaves had sunburn but we still ate lots of raspberries this season,” said Elaine. “I am thankful I had watched the news that night.”
I reflected on a Powell River Garden Club presentation from April 2018, Resilient Gardens in a Changing Climate by Dr. Linda Gilkeson, one of Canada’s most well-known authorities on organic gardening and pest control. In her presentation, Dr. Gilkeson provided a wealth of information on what is happening to the plant species on the west coast, and how to best prepare for and respond to challenging conditions in a changing climate.
I remember her saying that these days you have to be ready to protect less hardy plants by covering them with either shade cloth or reemay, and sometimes even alternate from one to the other as the weather becomes increasingly unsettled, even over the course of a day.
Margaret’s descriptions of her tomatoes match that of Dr. Gilkeson’s description of fruit experiencing stress brought about by heat and drought. She said plants can tolerate heat if there is sufficient water, and can survive drought in lower temperatures. But plants have low tolerance when both occur simultaneously.
Dr. Gilkeson’s presentation has been updated and is accessible online at lindagilkeson.ca/pdf/Resilient%20gardens%202019.pdf or can be found by doing a search for Linda Gilkeson Resilient Gardens For a Changing Climate.
Growing plants is always a challenging and rewarding endeavour. There are always successes that compensate for the failures and keep us excited about starting over next year.
Dealing with weeds, pests and watering can be problematic and frustrating. In addition, now having to constantly be aware of the shifts in what, when and how to plant to lessen the negative effects of a changing climate brings gardening into a whole new dimension and perspective.
But, as Margaret says: “Just the same, gardening is a lot of fun. You have to really love it to already be planning for next year.” And we do!
Lesley Mosely is president of Powell River Garden Club.