This month’s 40 °C plus sweltering heat and minimal rainfall has taken a toll on suburban landscapes. Annual flowers planted just last month have yellowed or are stunted; the usually upright foliage of rhododendrons and smooth hydrangeas have retracted into protection mode to prevent excessive water evaporation; and thirsty perennials like astilbes and bleeding hearts have either gone dormant or withered away completely.
But the greatest evidence of drought and heat is seen in lawns without irrigation systems. Mine is almost completely devoid of colour with the exception of the sparse weeds poking through. Now, with every footstep, the once green turf no longer springs back, but instead emits a crunching sound louder than my teenaged son munching his morning bowl of cereal. The forecast isn’t that hopeful either with little rain and another heat wave looming for Montreal after the brief respite we are experiencing at the time of this writing.
So, what’s a gardener to do to protect plants from heat and drought? A recent trip to southern Greece — where beautiful plants flourish despite being one of the driest, hottest climates — has left me feeling cautiously optimistic. There, I witnessed an abundance of beautiful plants — floriferous roses, mammoth geraniums (Perlagoniums sp), overflowing, aromatic herbs like rosemary, oleander and olive trees embellishing roadways, and fuchsia bougainvillea radiantly making up for any lacklustre terrain. Shrubs like lantana, which is grown as a mere annual here, sprout from dusty gravel in the leanest of Mediterranean soils. Once established, such xerophytic plants relish the heat.
We have our own drought-resistant plants here, more varieties than you could imagine. Theresa Amorosa, manager of West Island Nursery, which has been operating since the early 1980s, pointed out a dozen or so plants in the brief period we perused the perennials section of her family’s nursery. Sedums and sempervivum (hens and chicks) which store moisture in their thick leaves and have thick, waxy coatings that help protect them from water loss, make them ideal plants for xeriscape gardens, rockeries and containers. Two of my favourite sedums are variegated s. ‘Autumn joy’, which has an upright growth habit and s. rupestre ‘Angelina’ whose trailing yellow summer foliage changes to a bright orange in fall.
Russian sage, salvia, artemisia, lavender, sea holly and annual verbena bonariensis all thrive during a summer heat wave in my sunny garden; their silvery-metallic foliage, like a sunscreen, has a reflective quality, to protect them from an overabundance of sunshine.
Amorosa also points out perennials with a long season of bloom, such as liquorice-scented anise hyssop ‘Blue fortune’ (Agastache foeniculum), common yarrow and coreopsis. They attract hummingbirds, bees and butterflies as they battle the heat. Ornamental grasses too, and deep-rooted trees and shrubs add multiple seasons of interest to gardens, are heat and drought resistant, and require very little effort to grow.
So, if you thought cactus is the only plant that can endure a heatwave, you were wrong.
To help plants resist drought and heat stress, regularly incorporate organic matter such as compost into the soil, which will boost its water holding ability along with plant health. Water plants only when necessary, and when you do, water deeply and infrequently near the plants’ root zone.
As for the lawn, no plant is thirstier. During extreme heat without rain, simply let the lawn go dormant. It will return green and lush with cooler temperatures when gardeners will soon be once again longing for the dog days of summer.
Elaine Sanders can be reached at www.solutionsjardins.com