The genius of xeric plants
Sigrie Kendrick – Jun 17, 2026 / 11:00 am | Story: 620178
Photo: Judie Steeves
A bright, colourful xeriscape garden with the right plants will withstand, and even thrive in, drought conditions in the Okanagan.
Drought tolerance isn’t only about anatomy, it’s also about strategy.
There is a common misconception that drought-tolerant plants are simply tough plants— survivors that endure poor conditions through grit alone. The truth is far more fascinating and takes a dive into the biology of drought-tolerant plants.
The plants that thrive in the Okanagan’s hot, dry summers aren’t suffering through the season. They are engineered for it, shaped by millions of years of adaptation.
Understanding what makes those plants work isn’t just interesting science but the foundation of smarter gardening in one of Canada’s most water-stressed regions.
Much of what makes a drought-tolerant plant exceptional happens where we humans can’t see it. Root architecture is the first and perhaps most important adaptation.
Okanagan natives such as Bitterroot (Lewisia rediviva), Arrow-leaf balsamroot (Balsamorhiza sagittata), and Prairie smoke (Geum triflorum) develop stout, fleshy taproots one to three metres deep, accessing subsoil moisture that shallow-rooted ornamentals never reach. Those taproots also serve as storage organs, stockpiling carbohydrates and water that sustain the plants through the harshest stretches of summer drought.
So efficient is this adaptation that Bitterroot, one of our region’s most iconic natives, can survive being uprooted for weeks and still revive when replanted.
Other species such as Bluebunch Wheatgrass (Pseudoroegneria spicata) and Blanketflower (Gaillardia aristata) develop dense, wide-spreading fibrous root systems that fan out through the upper soil horizon, capturing even the lightest rainfall before it can evaporate. Unlike deep taproots, those fibrous networks maximize surface area, drawing moisture from a broad swath of soil.
Drought-tolerant plants also invest heavily in their root systems relative to their above-ground growth. A modest-looking plant in your garden may be hiding twice its visible mass underground, allowing it to access moisture deep within the ground during the dry months of July and August heat.
Above ground, a plant’s drought strategy is written plainly in its foliage if you know how to read it. Silver and grey leaves, so characteristic of Okanagan favourites like Artemisia and Salvia/Sage, aren’t simply a colour choice. Reflective leaf surfaces bounce back intense ultraviolet radiation, lowering leaf temperature and dramatically reducing water lost through transpiration.
Run your fingers along the leaves of many of these plants and you’ll feel the fine hairs, known as pubescence, which create a humid micro-layer at the leaf surface, buffering hot, desiccating wind.
Smaller leaves are another common signature. Reduced surface area means reduced water loss, which is why thyme and other tiny-leaved plants handle heat with such ease.
Waxy cuticles serve a similar purpose, forming a vapour barrier on the leaf epidermis that cuts transpiration in dry conditions.
Some plants go further still with Sedums, Sempervivum and other succulents storing water directly in fleshy leaves and stems which act as a reserve they draw upon when rainfall disappears for months at a time.
Many native and non-native xeric species, have evolved a process called CAM photosynthesis. CAM (Crassulacean Acid Metabolism) photosynthesis is a specialized water-saving adaptation found in many drought-tolerant plants.
Unlike standard photosynthesis, which requires plants to keep their stomata open during the day, losing significant moisture in the process, CAM plants open their stomata only at night, when temperatures are cooler and evaporation is minimal. During these nighttime hours, they absorb carbon dioxide and store it as malic acid in their cells.
When daylight returns and the stomata close, the plant converts that stored acid back into CO₂ and uses it to drive photosynthesis internally. This clever biochemical workaround allows CAM plants to photosynthesize in full sun while losing very little water, making them exceptionally well-suited to the Okanagan’s hot, dry summers and one of the reasons xeric species can thrive with minimal irrigation.
Many Okanagan native plants are phenologically clever, front-loading their growth and reproduction into the cooler, wetter weeks of spring before summer heat arrives. Bulbs and early-blooming perennials set seed and begin retreating underground before the driest months even begin.
The Okanagan receives less than 300 millimetres of rainfall annually in many areas. Planting species that require supplemental irrigation through a dry-summer climate isn’t gardening, it’s maintenance. Choosing plants that have spent thousands of generations adapting to our semi-arid conditions means choosing landscapes that sustain themselves, support native wildlife and remain beautiful even in the driest years.
Drought tolerance, in other words, isn’t a compromise, but a triumph of design.
Go to the OXA website to join it and learn more about xeriscape. Make use of the searchable plant database. okanaganxeriscape.org
Sigrie Kendrick is executive-director of the Okanagan Xeriscape Association and a master gardener.
The Okanagan Xeriscape Association is grateful for the ongoing financial support of the Okanagan Basin Water Board and is proud to be collaborating on the Make Water Work campaign. Check out the Make Water Work plant list at makewaterwork.ca
Photo: Contributed
The Okanagan receives less than 300 millimetres of rainfall annually in many areas. Planting species that require supplemental irrigation through a dry-summer climate isn’t gardening, it’s maintenance.
This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.
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