How to help your garden recover from the heat -- and how to prepare for hotter summers
Well, the tomatoes are happy.
All the unseasonably warm weather has made some plants thrive while others have gone limp from the heat. There is nothing you can do about scorched and damaged foliage except to snip it off once the heat wave is over.
Hydrangeas and conifers have really suffered, but most plants will outgrow the heat damage. Give crispy hanging baskets and potted plants a week to revive after watering and cooler weather. After that, if they haven’t bounced back, think about breakfast and call them toast.
Here are some hot garden tips to help navigate the warmer summers of the future.
1. Grow more edible heat lovers (many from South America, Africa and the American South)
This means veggies such as tomatoes, squash, cucumbers, eggplant, peppers and onions. These edibles love hot days and warm nights. They will need water, often staking and always great soil that holds some moisture, but they have root systems and foliage that do well in heat waves. Okra and melons also take the heat but are not dependable here in Western Washington.
2. Grow more heat-loving flowers
A flower bed up against the west or south side of the house can heat up enough to wilt many garden favorites, especially if near concrete. There are many plants that will bloom like crazy during hot weather. Look for portulaca, geraniums, lavender, most petunias, sweet potato vine, scavolea and my top recommendation: lantana.
The tropical colors of lantana vine make this a bright spot in any heat spot, and the spreading nature can cover a lot of ground and block out a lot of weeds. All this and lantana cleans up after itself. The spent blooms drop petals quickly as new flowers form.
In southern climates, lantana is grown as a perennial or even a shrub, but here in Washington it is considered an annual that will die when winter arrives.
3. Grow more drought-resistant, heat-loving shrubs
Purple or golden Spirit Smoke tree, potentilla, spiraeas, barberries, junipers, and shrub roses (especially the Flower Carpet roses) are just a few of the great choices for drama without all the watering.
To look for more drought-resistant plant ideas, start to notice what shrubs have survived in parking strips, school yards and around old, abandoned properties that do not have sprinkler systems.
4. You must mulch
Covering the bare soil with a frosting of bark chips, compost, gravel or even wine corks will not only shade and cool the soil but seal in moisture as well.
You do not need to buy a mulch if you have trees on your property. Use old, rotted leaves or bag up some fallen leaves when you rake them from your lawn this fall and let them rot inside a plastic garbage sack. Poke holes into the sack for more air. Then in the summer you can empty these sacks of moist and decaying leaf mold on top of your shrubs, perennials and annuals for a soil-cooling, water-saving mulch around the roots.
July is not too late to mulch your plants. Just water first, then add the mulch.
5. Water wisely
Water in the morning or evening to cut down on evaporation, and water deeply but less often. This means once a week for several hours rather than giving plants just a light sprinkle every day.
Infrequent and deep watering will train plant roots to search down deep for moisture and make them more independent. This is especially true for lawns.
Containers gardens and hanging baskets may need daily water.
6. Water, then water again to tap the cap.
Use the beauty of “the cap,” or capillary action, to draw water deep into the soil so it can be stored until your plants need it.
This means turning on the sprinkler or soaker hose for about 10 minutes then turning the water off for an hour so the water trickles down. Now turn the water back on. The moisture that has already been absorbed by the soil will pull the new water down more quickly due to capillary movement. This works like a magnet to attract moisture to plant roots.
Marianne Binetti has a degree in horticulture from Washington State University and is the author of several books. Reach her at binettigarden.com.
This story was originally published July 3, 2021 at 5:00 AM with the headline "How to help your garden recover from the heat -- and how to prepare for hotter summers."