Don’t let summer sun and heat harm your succulents! Heat, unlike frost (temps 32 degrees F and lower), usually isn’t a concern for succulents. Although some tend not to thrive in temps above 80 or 90 degrees F, the majority can handle more than you’re personally comfortable with…as evidenced by greenhouse temperatures that soar into the triple digits on summer days. However, heat plus sun can be deadly to succulents. Unless they’re desert cacti or agaves, most smooth-leaved succulents need sun protection in summer, especially above 80 degrees.
If you live in an arid climate like Southern CA’s and grow succulents in the open garden (as I do) ~
— Know your property’s orientation to the sun. In North America, plants growing on your home’s north side will get the least amount of sun exposure; those on the south, the most. East-facing gardens like mine get morning sun and afternoon shade. Gardens facing west have afternoon sun and morning shade.
— “Bright shade” (no direct sun but not deep shade) is ideal for non-desert succulents in mid-afternoon when temperatures peak. Bright shade is essential for low-light succulents such as haworthias, gasterias, euphorbias, faucarias, sansevierias, echeverias, and anything light-colored or variegated. (Of course there are exceptions; for the requirements of specific plants, see the “Succulents A to Z” chapter of Designing with Succulents.)
— Whenever you buy a new plant, notice where it was located in the nursery. Was it out in the open or beneath shade cloth? Even if it’s a “full sun” succulent—like an agave—if it was growing in a sheltered area, it’ll need to be “hardened off” (shaded, especially in the afternoon) until it acclimates. Such exposure is similar to tanning: Start with half an hour of sun and increase it by an hour or so each day.
— Give aloes and crassulas enough sun to turn hues of red and orange but not so much that leaf tips shrivel or burn—at least half a day, ideally morning. (See “How to Stress Succulents and Why You Should.”)
— Because sunburned stems are less able to transmit moisture from roots to leaves, cover exposed, horizontal stems of trailing succulents (aloes, senecios, othonna and the like) with dry leaves or mulch.
— Protect newly installed plants and in-ground succulents susceptible to sun-scorch with temporary shade structures. I use old window screens secured with bricks, but you can buy shade cloth at any home improvement store. Leafy branches trimmed from trees works, too; insert branches in the ground next to the plant you want to protect, making sure it’s shaded on the side that gets the most sun.
— Plant trees and shrubs that will provide shade where needed during long, hot summer afternoons. (For low-water varieties good in succulent gardens, see the Companion Plants chapter of Designing with Succulents, 2nd ed.).
When it’s too late (what sunburn looks like)
Beige patches on succulents indicate sunburn. Cells have been irrevocably damaged, which turns them white or putty-colored. This looks similar to frost damage, but instead of leaf tips, you’ll see patches on leaves. An otherwise healthy plant will outgrow the damage. If marred areas are on outer leaves, so much the better; new growth from the center of the rosette will conceal sunburned areas over time. In any case, lower leaves, damaged or not, naturally wither and fall off. Depending on the succulent and the season, recovery from sunburn may take several months to a year.
How to Water Succulents in Summer. OK, we all know that succulents are low-water plants. But they’re not “no-water” plants. Although they may survive without irrigation during the heat of summer, they’re unlikely to be lush and healthy. Be sure you… [continue reading]
Succulents, Sun and Summer. On an 89-degree day in my garden, I show you what’s in bloom and lookin’ good (or sadly dreadful), and explain how to evaluate the health of your in-ground succulents, small and large.
Twelve Low-Water Trees for Succulent Landscapes. I help you evaluate garden areas in need of shade and select trees to plant when the weather cools in the fall.