Plants Keep You Cool

Wild geranium and wild columbine by Alice Kong.

We’ve already experienced a few 30 degree days this year and we’ll likely see more because of climate change. With summer just getting started, it’s a good time to think about ways to stay cool.

The best way to keep cool in your yard is to add more plants. Think about it: If you were outside on one of these hot summer days, would you rather be in the middle of a parking lot or standing under a tree? You probably answered tree because it provides cooling shade. But did you know shrubs and flower gardens can also keep you cool?

A garden full of shrubs, wildflowers and groundcovers can feel cooler because of evaporation and transpiration (or evapotranspiration). These two processes move water into the air to create a cooling effect.

As water evaporates from the soil, and plants transpire or release water vapor into the air, local temperatures decrease. Areas with hard surfaces, like parking lots, hold and radiate the sun’s heat, increasing temperatures and making it feel up to 12 degrees Celsius hotter in larger cities.

You can create a cooler yard by planting a shade tree and adding shrubs, wildflowers and groundcovers. Choose red oak or hackberry to create a large shade area. If you have a smaller yard, try serviceberry or alternate-leaved dogwood.

To create a more dynamic garden, add shrubs like purple-flowering raspberry or maple-leaf viburnum, flowers such as large-leaved aster, foxglove beardtongue or wild geranium, and low-growing groundcovers like wild strawberry, barren strawberry or Canada violets.

Photo: Wild geranium and wild columbine by Alice Kong.

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