The heat is on
In Calgary it usually gets hot during the Stampede, but I took no chances this year. I’m on holidays in Kelowna sitting lakeside in 30 C heat, hoping plants at home are surviving the extremes in Calgary weather. As long as water is plentiful, extra sugar gathered from the sun produces earlier tomatoes and peppers, bigger pumpkins and fatter carrots so I am hoping crops will start maturing while I am away. Heat also causes big flowers such as roses and geraniums to fade faster so I did a little preventive deadheading before I left. By this time of year, it is too late to move plants around in the garden but here are some hints to ease the pain of volatile weather.
Some like it cool
Some plants will wilt when grown in full sun. Broad-leaved, soft plants like Hosta, Hydrangea and Ligularia varieties will wilt even if the soil is moist because they simply can’t keep enough fluids in their big leaves to stay fully hydrated during hot spells if planted in full sun. If they get too much direct south or west sun, they will wilt, at least temporarily, and gardeners may panic and pour water on them, even if the soil is moist. A north-facing slope is cooler than a south-facing one, and a shady spot by the house or under a tree is best for these floppy leaved plants. I snapped a photo in the very hot climate of Dubrovnik, Croatia when I saw a gardener there had propped a beach umbrella over hydrangea. In reality, most gardeners aren’t willing to protect individual plants from sun, so instead they grow water-wise plants.
Some like it hot
Bergenia cordifolia (elephant ears) are large-leaved plants with a waxy coating. They will not wilt in hot weather and don’t need moist soil so are considered water wise. Cactus, yucca, hens and chicks and sedum among others only open their “breathing pores� at night so they will not lose moisture to the dry hot air during the day and will not wilt. I visited a wonderfully diverse water-wise garden at Kelowna’s H2O Centre. Most of the plants used in Kelowna (listed here: http://okanaganxeriscape.org) will work in Calgary. The City of Calgary’s drought-tolerant list is at http://bit.ly/132qP8K.
Giving plants what they want
Pumpkins, peppers, tomatoes and grape vines prefer it hot and do best when heat builds in the soil. I am only visiting and not gardening in the Okanagan, so in my colder, north-facing garden at home, I use infrared technology (IRT) mulch over the soil around my pumpkins and squash to keep it hot (http://bit.ly/16uWvBE). This mulch traps the warm infrared light in the soil, a situation ideal for heat-loving vegetables of all kinds.
Most non-fruiting plants prefer cool soil so mulches such as bark, wood or gravel are better in the landscape. These mulches allow infrared light to hit the soil and bounce back into space instead of staying trapped. This keeps soil cooler and helps preserve moisture.
Water restrictions
Watering bans have been lifted in Calgary, but gardeners have been asked to be conservation minded because of the stress on Calgary’s water treatment plant during and after the flood. During our fluctuating summer weather, gardeners can water by hand in the early part of the day only. There is never a reason to overhead water during the day, as most of it will evaporate before it helps plants.
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