What is a succulent?

Many plants have evolved to meet the challenge of scarce water. Those that have met that challenge by storing water in their tissues are called succulents. Cacti are succulents, but many people separate them from other water-storers; hence, our society’s slightly inaccurate name: Cactus and Succulent Society of Alberta. It works out pretty well, however, because in most cases people who are interested in cacti are also interested in other succulents, and vice versa.

This little outline focuses on the non-cacti succulents. While cacti are native to the Americas, other succulents turn up worldwide—in deserts and other dry areas. Through “convergent evolution,” many plants have developed similarly, even though they are unrelated. Some succulents have prickles like cacti; others grow from broken pieces scattered by animals or wind, like many cacti. (This feature makes many succulents easy to grow from cuttings.) These succulents can be tiny and shrink away into the soil during dry seasons or huge and stand up like very large trees.

Succulent strategies

How might a plant store water? Well, just about any way of doing so has been adopted by some plants somewhere. A common strategy is to have fat leaves that can swell when water is available and shrink or even fall off as they pass their water into the centre of the plant. Another, often going with fat leaves, is to have a fat stem, trunk or branches. Some succulents get so fat when they can that they develop rather obese-looking stems called caudexes, storing a very large amount of water that can last the plant through much dry time. A third approach is to have fat roots or tubers, or rhizomes and other connections among plants, storing water underground. Many succulents, including cacti, have developed such a fine-tuned response to dry conditions that if they are too wet (such as by a well meaning owner watering them too often), they rot away.

When you have worked hard to store your water, you don’t want animals or insects to take it away. Hence spines and prickles (which also can help cool the plant, further conserving water). Also, some succulents have irritating or downright poisonous sap, discouraging sucking insects. This sap can be quite thick and full of latex so that when the plant is wounded, the sap develops a rubbery plug to hold in the water and avoid a hole that insects might use. (The rubber tree is from a family of succulents, though it grows in rain forests and isn’t succulent itself.)

There are other strategies for dealing with dryness, sometimes going with succulence, sometimes not. Non-succulent plants that just dry out and struggle along until the next water include the ocotillo of the south-western U.S. deserts, bromeliads and air plants and the common house plant dracaena. Some reproduce trying to carry the line on even if the first plant dies in the dry—some spurges that are a nuisance in Alberta do this, as of course do familiar scourges like crab grass and dandelion (though these have a semi-succulent strategy in having thick or joined root systems that can bounce back if the above-ground plant dies).

Families of succulents

There are thousands of succulents, and within each group there are exceptions to every description. But here are some common groups:

• Non-stemmed leafy groups: Agaves, Aloes, Yuccas, Sansevierias (“snake plant”) and
Sempervivums (“hen and chicks”);

• Irritating sap groups: Euphorbia family (including the Crown of Thorns) and Milkweed
family (some prominent members of these families are not succulents, like spurges,
that are euphorbias, and the milkweed itself, favourite food of Monarch butterfly caterpillars);

• Usually small and fat-leaved groups: Crassulas (including the jade tree), Senecios,
Kalanchoes, Haworthias, Aeoniums, Echeverias and Sedums;

• Fat caudex groups: Adeniums, Fockeas, Pachypodiums (including “Madagascar palm”),
Beaucarneas (“ponytail palm”) and some Cycads (such as “Sago palm”);

• Downright odd groups: Lithops (“living stones”), Stapelias (“carrion plant”) and
“Medusoid” euphorbias (with long snake-like branches around a central caudex, like Medusa’s hair).

Succulents hardy in Alberta?

Sad to say, but very few succulents are hardy in Alberta. Nearly all the plants listed above are strictly house plants in Alberta, at least in the winter. Not only is it too cold for many that store water and would burst if frozen, but most of Alberta is not really dry enough to prompt evolution in a succulent direction. There are native cacti in Alberta, especially in the southern badlands, but also all the way up to the Peace River country, which have adapted by letting themselves dry out in the cold weather. And some sedums can be found growing in rocky areas near the mountains.

A few introduced succulents do fine in Alberta. A prominent one is a Sedum: “Autumn Joy.” This plant grows to half a metre high and has great clusters of flowers in the fall. Also common are Sempervivums: these “hen and chick” clusters of low plants put up long and extravagant flower stalks in the summer. Some yuccas and non-native cacti also grow well outside here.

Succulent care

Though succulents are largely house plants in Alberta, most do like a lot of sun, especially the ultraviolet rays they get only by being outdoors. So succulent fanciers often put their plants outside for the summer (though in some summers they need some protection from extra rain and occasional cold). If you do put your plants outside, introduce them to the sun gradually—just like us, they can sunburn. (Yes, even cacti can sunburn!) Under good conditions, look for flowers in the summer. Many succulents are prized for their foliage and general look, as they often have small flowers that are pretty but only if you look closely!

The main care is to treat succulents like cacti indoors. Give them lots of light, sunny windows if possible (though some like Sansevierias are happy in lower light and others, like Haworthias, can get rather dark and dried-looking if in too much sun) and water them sparingly, especially in winter when they are not growing.

Fertilize mainly when they are growing.

They should be planted in pots that are not too large, maybe even seeming a bit smallish to you, so that they can dry out between watering, in sandy or gravelly soil that doesn’t hold water. Succulents are adept at grabbing water as it passes their roots, so they don’t like to sit in damp soil and many will unfortunately rot easily. Make sure their pots drain well – don’t ever let the pots sit in dishes of water. Some succulent fanciers water their plants hardly at all between November and March – only giving a little when the plants seem to look too parched. They like to be cool in winter.

Unfortunately, succulents are just as susceptible to bugs as are other house plants. The main two are mealy bugs (white, yeasty-looking patches especially in crevices) and red spider mites (too small to see without magnification, but their webs and the brown patches especially on the underside of leaves can be seen). Washing the plant in soapy water, or just water, or spraying with rubbing alcohol can help, but especially in Alberta’s dry winters, bugs are just a fact of life.