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Steele: Caring for your shade trees in the heat

Shade trees create natural, free air conditioning.
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Drought-tolerant honey locust trees provide shade and add beauty and value to this street in old Glenmore. -Photo credit: Gwen Steele

Now that it’s hot, have you noticed that all the shaded spaces in parking lots get filled first?

Imagine how nice it would be if even one quarter of the spaces were shaded. Cars would stay cool so less air conditioning would be needed. Parking lot pavements would radiate less heat, reducing the heat effect in the city. Parking lots would look more appealing to shoppers.

A tree-lined street is much more inviting and cooler than one with stark pavement.

A park with mature trees is more appealing to walk in than just grass.

Our homes are much cooler if we have shade trees. They create natural, free air conditioning, particularly if growing on the south and west sides.

Knowing it takes a long time for a tree to grow, I decided to ask Jeanette Merrick, arborist at Trees for Life, to give me some tips on how to help our trees through the heat wave.

This is what I learned from her:

Just as we suffer from the heat, so do trees. Well-established, mature trees, in good soil, generally have a good root system so can manage unless the heat wave is prolonged. Trees in poor, fast-draining soil will need supplemental water.

When watering a tree it is best to give them a long, slow soaking so the water has a chance to go deep. Watering at the drip line is the most effective. That is where the tree’s feeder roots are.

Young trees need to be watered regularly for the first three years to help them get their root system established. After that they will need a good, long soak during hot weather until they are mature.

One way to do this is with a gator bag. It holds five gallons of water. Water is slowly released through tiny holes.

Trees that have been stressed, such as by nearby construction, need extra care with attention to watering.

If you are fortunate enough to have boulevard trees, be sure to give them a long, slow soak if they are young or show any signs of stress.

Mulching is another way to help your trees. Mulch helps preserve moisture in the ground, prevents the formation of a hard crust on the soil surface and discourages water-thirsty weed growth.

Remove weeds and soak the ground first, then add a four inch layer of material such as Glengrow or composted wood waste. Spread flat around the tree and out beyond the drip line. Keep the mulch a few inches away from the trunk.

I invite you to join me on Thursday, Aug. 2 at 7 p.m. for a free presentation at the unH2O Xeriscape Demonstration Garden, 4075 Gordon Drive in front of the H2O Aquatic Centre.

I’ll be talking about the plants that are in bloom, characteristics of drought tolerant plants, and answering questions about water-wise gardening.

Gwen Steele is executive-director of the non-profit Okanagan Xeriscape Association. Learn more about Gardening with Nature and plants for the Okanagan on the website at www.okanaganxeriscape.org