But our treasured succulents don’t have to unduly suffer
We are fond of referring to succulents as the ultimate easy-care plants but many species can suffer serious damage or death if exposed to elements they aren’t predisposed to tolerate.
If you live in an area that experiences hard freezes (especially moreso than just a freak episode here and there), be prepared to bring cold-adverse species inside, finding them a comfortable spot with good airflow and light. Rotate pots 180 degrees every week or so to help prevent stretching. Before bringing plants indoors, remove any dead leaves as well as debris from pots and check for pests. When and if the weather warms up during the day, you can periodically bring them outside for some light-basking time. (And when the freezing weather ends in spring, gradually reintroduce your plants to the sun.)
For landscape gardeners living in borderline climates for year-round outdoor succulents, a south-facing slope is the best spot to plant frost-sensitive varieties, plants such as aeoniums, crassulas, kalanchoes, euphorbias, and many aloes. In the case of those succulents, borderline would generally be Zone 9b (25-30 degrees Fahrenheit), possibly Zone 9a (20-25°).
Even if temperatures occasionally drop below 32 degrees, many succulents, once established or in the right location, can handle chill better than one might expect. Landscape plants, insulated by earth and rocks, are able to withstand such weather better than potted plants. Your garden likely has microclimates that are warmer than exposed areas. Walls radiate heat, as do boulders, pavement, and hardscape features (such as a retaining wall). Cover such as an eave or tree branch will provide some frost protection.
The colors of the leaves of certain succulents, notably aloes, echeverias, and jades, will intensify when they are stressed. Too much, though, could result in unsightly leaf scarring, or frost burn. But no need to despair. While frost burn is no fun, plants are resilient and can recover barring persistent abnormal chilliness. A key factor in plants weathering frost or freeze episodes unscathed or nearly so is the duration. If you tend a Zone 10a (30-35°) garden, reliably experiencing a few frosty mornings each winter, do not fret…you are the envy of succulent & cactus nerds everywhere in the U.S.! Well, except for maybe those in the ultimate succulent plant banana belt of Zone 10b (35-40°). Fill your space with Zone 10-rated echeverias if you’d like and just be prepared should frost-possible periods pop up in the forecast come wintertime.
Having said all that, don’t set a plant out in the ground a month before winter and expect that it will be fine if excessive cold or rain comes. The plant, its roots not yet established, will have virtually no resistance for stressors. Typically, it is best to plant directly out in the garden several months prior to give the plant enough time to be acclimated for the next winter, ideally as early in spring as possible.
Those in more temperate climates can move their potted lovers of light — if not so much for heat, such as echeverias — to sunnier spots from where they were located during summer. If a winter warm spell comes, not unusual out here in SoCal, normal water is fine, but cease before more characteristic seasonal temps and/or rain return so that roots are not sitting in cold and wet soil for days and days before drying out.
To enhance cold tolerance:
- Establish root systems months prior to the first frost.
- Plants in the ground vs. containers are better able to tolerate cold temperatures.
- Use cloth, newspapers, a tarp, or some other covering or blanket.
- Plant near south-facing structures (and/or heat-radiating elements such as rocks) to provide the most sunlight and protection.
- Even the slightest cover, such as an eave or tree branch, will provide some frost protection.
- Succulents and cacti can better deal with some cold if it’s a dry cold.
- Even with famously cold-hardy succulents such as sempervivums, it’s a good idea to allow your new plants to ease into winter with time to acclimate to the cold.
Cold isn’t the only consideration. Rainstorms aren’t necessarily a succulent’s BFF either, especially prolonged events or serious deluges. If your potted plants have already gotten a healthy soaking from Mother Nature in a given week, move them to spaces protected by cover to prevent rot or other ill effects. Summer growers generally like to chill out during winter, preferring to stay on the dry side during their resting period. Refrain from fertilizing them during this time as well. Winter growers such as aeoniums will appreciate the water.
Succulents are often associated with warm climates, though there are many varieties that can withstand bone-chilling winters, at least for a spell. Semps and many sedums can tolerate subzero temps, as can many Opuntia species. In fact they’ll take an insulating blanket of snow over lots of cold rain.
Preparing your potted plants
- Try to situate the potted plant as early in spring as possible so that it is fairly well acclimated to most of the climate changes that might occur in that position (sans winter).
- Never buy a plant late in the year (particularly one that was just shipped to a store from a climate controlled greenhouse), and expect it to thrive in cold weather.
- As soon as the heat allows, or lack of it, begin to water somewhat less.
- If you are going to fertilize, make sure the last time is in September and is a lot more diluted.
- Attempt, if possible, to have the plant somewhat near a structure, or near another plant that can provide some shelter.
- Observe the plant. Blanching, leaf spots, leaf drop, not growing, etc are all signs of a possible problem.
- And keep that frost cloth handy!
Below are some of our favorite chill-OK species, starting with the hardiest first. This list is not meant to be a guarantee that every specimen represented here will tolerate frosts or freezing weather for hours, days, or weeks on end without some ill effect.
Sedum reflexum ‘Blue Spruce’Sedum reflexum ‘Blue Spruce’ — Zone 4a (-30° F)
Sedum spurium — Zone 4a (-30° F)
Nearly all sempervivums — Zone 5a (-20° F)
Many yuccas — Some to Zone 5a (20° F)
Dasylirion wheeleri (desert spoon) — Zone 6a (-10° F)
Hesperaloe parviflora (red yucca) — Zone 7a (0° F), possibly as low as 5a (-20° F)
Agave parryi (Parry’s agave) — Zone 7a (0° F)
Agave parryi truncata (artichoke agave) — Zone 8a (10° F)
Calandrinia spectabilis (rock purslane) — Zone 8b (15° F)
Oreocereus celsianus (old man of the Andes) — Zone 8b (15° F)
Oreocereus trollii (old man of the mountain) — Zone 8b (15° F)
Echinocactus grusonii (golden barrel cactus) — Zone 9a (20° F)
Senecio mandraliscae (blue chalk sticks) — Zone 9a (20° F)