Signs of drought stress in lawns and garden beds are common these days. The hot, dry weather we are experiencing can make us a slave to our landscape if we are scrambling to keep our plants alive and lawns looking lush and green.
Water is an important nutrient and plants need more than just a sip. How often and how deeply should you water during a drought period? Maintaining healthy growth really does depend on a number of different factors. Plants have built-in mechanisms for survival — to a point. A lawn, for example, will go into a dormant stage during a mid-summer drought when it receives little or minimal irrigation. In some cases the entire lawn may turn brown or exhibit crunchy brown patches. While grass ceases growth when there is a lack of adequate rainfall or supplemental irrigation, weeds proliferate and so do chinch bugs.
Praying for rain? For much of this summer in southern Manitoba the skies have never seemed so blue. News reports of heat waves in areas across Canada this summer, especially the Prairies, have referred to "uncharted territory for sustained heat" (Environment Canada). A brief shower or a torrential downpour does little to infiltrate heavy clay soils, particularly if they are compacted. The small pores between clay particles can hold water tightly and make it unavailable for plant uptake.
Smart watering during drought periods calls for supplemental irrigation to be applied properly. Water when the soil is dry five cm below the grass and wet it to about 15 cm deep. To measure the amount of irrigation water being applied, set out tin cans or glass jars on your lawn and record how long it takes before the containers hold five cm of water. The best time to water lawn is in the early morning. During hot, dry periods lawn should be watered a minimum of once every two weeks to protect the crown tissues, which are near the soil surface.
Alternatively, frequent light watering results in shallow roots, which can make your lawn even more vulnerable in sustained periods of drought. Sheldon Gesell, owner of local fertilizer manufacturer Dirt n’ Grow, recommends using an organic fertilizer with calcium sulphate, which helps to break down heavy clay soil and create more pore space. "By opening the microscopic pore space, roots are able to penetrate downward so they can access more moisture," Gesell says.
Timing matters. With fall just around the corner, applying a high nitrogen synthetic product in mid-August will only result in a flush of new vegetative growth at a time when plants need to get ready for winter dormancy. However, Gesell says, organic products provide a much slower release of nitrogen and can be applied until the September long weekend without causing detrimental effect to woody plants, perennials or turf grasses.
New plants are the least likely to tolerate drought stress. Yellowing leaves can be a sign of too little or too much watering. The first year in the garden is a critical time for establishing healthy root systems. If your garden is filled with plants with high-moisture needs, then the amount of energy (yours) and water required to keep them happy may have you rethinking your garden.
Cathy Shaluk owns Shaluk’s Garden Solutions, a local company that designs, installs, maintains and refreshes landscapes, both residential and commercial, including The Forks site and Upper Fort Garry Provincial Park.
Shaluk embraces native grasses and flowers: their extensive root systems and waxy coatings keep them alive during extended dry periods. "Many people mistakenly associate native plants with plants that aren’t showy or don’t present well," she says. "It’s all about how you plant and group them but also how you incorporate them with some of the higher-maintenance plants that we’ve fallen in love with."
Just some of Shaluk’s favourite native plants include purple coneflower (Echinacea angustifolia), tall meadow rue (Thalictrum dasycarpum), highbush cranberry (Viburnum trilobum), indigo bush (Amorpha fruticosa), Big Bluestem (Andropogon gerardii) and Joe Pye Weed (Eupatorium maculatum).
Native plant species have evolved to adapt to heavy clay soil that doesn’t infiltrate or drain well. Come the dog days of summer, native plants have never looked so good. That said, a newly installed native plant is reliant on adequate amounts of moisture or it, too, will begin to show signs of stress such as wilting or leaf drop which can lead to dieback.
"Right plant, right location" is the mantra for all gardens, but a warming climate makes choosing the right plant even more important. Shaluk takes heed of the information provided by Climate Change Connection, a program offered by Manitoba Eco-Network. Climate change will mean temperatures that are warmer than usual and longer growing seasons. More extreme heat will translate into drought which will affect our water resources. Southern Manitoba is expected to see an increase in winter precipitation, Shaluk says, which will cause a decrease in snow cover.
Planning your site to support these changes will allow you to continue to grow your favourite plants and to support their healthy growth. Well-drained soil with good aeration and fertility is key. You may want to consider a soil test. Understanding the components in your soil and the percentages of clay, sand and silt, Shaluk says, will help you to know which types of soil amendments you may need to add.
Shaluk suggests digging a spade into your soil about 15 cm deep and scooping it into a wide mouth Mason or glass canning jar. Try this in several areas of your yard. Fill half of each jar with soil and the other half with water, stir, and let sit for a day or two. Distinct colour bands gradually appear. The thickness of each band gives you an idea as to how much clay, silt and sand you have in your soil. You may find that different parts of your landscape have different percentages of the various components.
By referring to a soil texture triangular matrix, a tool commonly found on the internet, you will gain insight into your soil’s moisture characteristics. A soil sample that contains mostly clay, for example, is an indication that your soil has poor moisture penetration. To amend heavy clay soil, Shaluk adds soil amendments in spring to garden beds such as compost and peat moss which help to promote good drainage.
Many of us water our lawns and flowerbeds with potable water, which is costly to use. While water restrictions may not be in the cards for Winnipeggers, we’re likely to be paying a lot more for our municipal water in the future. It makes sense to capture and store rainwater for use in the garden. Applying a layer of organic mulch such as wood chips or shredded leaves helps to conserve moisture in garden beds. As mulch slowly breaks down and decomposes, it nourishes your soil.
Be mindful of your resources, time and energy.
NOTICE: Agassiz Garden Club presents it’s annual Flower Show, August 14 at the Lac du Bonnet Community Centre, 25 McArthur Ave., Lac du Bonnet. 1:30 p.m. to 7 p.m. For more details call Carol at 204-345-8429.