Watering tips to help plants survive this heat

Photo: Sigrie Kendrick

Choosing plants suitable to our hot dry summer climate is one way to conserve water used on the landscape, as this collection of stonecrops in the gravel garden at the Okanagan Xeriscape Association's demonstration garden on Gordon Drive in Kelowna.

Many communities throughout the Okanagan Valley broke heat records over the last couple of days with Kelowna recording a staggering 39.3 C on July 9, breaking the previous record set in 2015 of 38.6 C. Some of these temperature records date back to 1899.

No wonder our gardens are looking heat-stressed and crispy. How can we make the most of water in our gardens so they are more sustainable in the face of this unrelenting heat?

Planting appropriate trees and maintaining the health of existing mature trees are a vital part of making our communities and gardens more sustainable and must be implemented hand-in-hand with the rampant development our city is experiencing.

Not only do trees store carbon but they mitigate temperature extremes and provide habitat for wildlife. The shade created by trees substantially cools your landscape and home and reduces evaporation of water from your soil, all improving your landscape’s ability to better adjust to climate change.

Trees can also be planted to act as a windbreak, protecting your garden from the ravages of drying winds. Check out our plant database at www.okanaganxeriscape.org for xeric trees to suit your landscaping needs. You can tailor your search with criteria such as size, bloom time, foliage attributes, and light and water needs.

If you’re not ready to completely embrace xeric plants in your garden, at least plan on designing your landscape so that you group plants with similar needs together. Doing so will conserve water and lead to healthier plants as they will be less likely to be under or over-watered.

I can’t tell you how many times I have seen high-water-need plants on the same water zone as low-water-need plants. Either one or the other will be unhappy, often with xeric plants being over-watered, leading to root rot and ultimately death. Consider dense plantings in perennial beds as these densely-planted beds will shade the soil around the plants and decrease evaporation of water from the soil.

Mulching is one of the most important tools you can incorporate into your garden maintenance as it reduces evaporation and weed growth and regulates soil temperature, all while nourishing your soil, which leads to stronger, healthier plant material that is better able to cope with these temperature extremes.

How, and when you water are two crucial factors in the equation of making your water work smarter. One of the biggest mistakes I see, even among so-called professionals, is watering frequently but briefly This encourages the establishment of surface roots which are ill-equipped to deal with drought. It is much, much better to water deeply but infrequently as this establishes stronger root growth deeper into the soil as roots search for water.

Drip irrigation has been determined by the Regional District of the Central Okanagan to decrease your water consumption between 30% and 50%. This makes sense as drip irrigation supplies water to the root area of the plants where it is needed as opposed to spraying it in the air where so much is lost to evaporation, especially in these temperatures. The added bonus of drip irrigation is that it doesn’t spray a larger area of soil thereby encouraging weed growth. Pay attention to natural precipitation and adjust your irrigation accordingly.

When you water is just as crucial as how you water. The very best time to water is in the early morning hours as this allows the water supplied, to reach root depth and to sustain your plants before the heat hits. It allows any water on the foliage to dry therefore limiting fungal disease. The second best time to water is late in the day, at dusk, but attention should be paid to ensure that foliage is dry prior to nightfall to reduce the risk of powdery mildew and other fungal diseases.

As in years past, the Make Water Work challenge encourages homeowners to take the pledge to make water work smarter on their landscapes. By heading to the website and pledging say to ‘choose plants suitable to our dry environment’ you will become eligible to win one of two prizes of $500.

This pledge encourages you to make better choices about your consumption so there will be enough water for firefighting, aquatic health, and agriculture. It only takes a moment to make your pledge. Know your district’s water restrictions and abide by them, currently West Kelowna, Peachland and the Regional District of Central Okanagan are already on stage two water restrictions, which means outdoor watering is restricted to two days a week.

I will be touring Okanagan nurseries and garden centres throughout the gardening season, supporting the many benefits of the Make Water Work plant list and campaign. Keep an eye on our social media for my schedule and stop in to say hello and to talk all things xeriscape.

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.

Sigrie Kendrick is a master gardener and executive-director of the Okanagan Xeriscape Association.

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.