What to Do in the Garden in Extreme Heat: Tips for Climate-Resilient Landscapes

This summer has been hot—really hot. Gardeners across the globe have recently experienced the four hottest days ever observed, and by all accounts, this is the new normal. Late last year the U.S.D.A. released their new Plant Hardiness Zone Map, which shifted zones for many locations, including the Midwest and Northeast, into the next warmer half zone. So, what’s a gardener to do? We reached out to a group of garden pros who have experience in gardening in extreme heat to ask them how we can plant and maintain our gardens to better weather hot summers. 

Read on for their advice for picking plants, watering plantings, protecting trees, and more.

N.B.: Featured photograph above courtesy of Refugia, from Garden Visit: Refugia’s Quiet Revolution in Philadelphia’s Suburbs.

1. Stop planting.

After a particularly dry, hot summer in 2022, Claire Davis, an ecological garden designer in the Hudson Valley vowed: No more summer planting. “I decided that I wanted a cut-off date for plantings,” she says. “That super-dry, hot summer felt brutal for newly planted areas, and it was pretty miserable as a gardener trying to take care of them.” As a bonus, Davis says that pushing pause on planting has given her much welcome breathing space in her garden maintenance calendar. Instead of giving into the impulse to add annuals for “a little color” in midsummer, make detailed notes about when and where you lacked blooms, so you can make a plan to fill the gaps come fall.

2. Favor native perennials.

When you do add plants in the fall (or next spring), all the experts we spoke to placed an emphasis on using perennial plants native to your region because they are naturally adapted to the climate there. “For the most resilience in the heat, use mostly perennial native plants instead of seasonal annuals, because their root systems are more extensive,” says Ginny Stibolt, the author of Climate-Wise Landscaping, who gardens in Florida. She notes that forgoing annuals will also result in less disturbance of the soil, which helps build up humus, so that the soil stays moist even when it’s hot.