Quick reference guide

• Soil: well-draining soil. Use perlite, pumice, or other similar elements liberally.
• Pot size: compact to the plant/root size, potting up every 2-3 years if the plant begins to struggle. Fast growers sometimes need quicker upgrades!
• Light: filtered sun or bright indirect light, may need supplementation from a grow light indoors. More sun brings out stress coloration.
• Water: occasional deep watering. Allow to dry between waterings; keep dry over winter.
• Overwintering: hardy to 40-50°F, many tolerate light freezes if soil is kept dry.
• Fertilizing: once established, fertilize 1x per month during the growing season (spring-summer) using a balanced or high-potassium fertilizer at half strength.
• Propagation: easiest from cuttings for most varieties. Seeds may not grow true.
• Maladies: succumbing to root rot and mealybugs most common.

 

Detailed version 

Soil

Well-draining soil can't be over-emphasized. I use a mix of one-part perlite, one-part organic potting soil (which already has perlite in it). Larger-sized pumice and chunks of wood in cactus composts can help keep soil from compacting and staying damp.

A standard garden soil mix is too nutrient-dense and poor-draining to keep stapeliads happy long-term. In my experiments, they became lanky from the high-nutrition environment, were more attractive to mealybugs, and were also at higher risk of root rot because the soil stays damp longer after rain or watering.

Alternatively, go for a free-draining inorganic soil using materials like lava rock, pumice, perlite, grit, and sand. Inorganic soils can take more care in some ways so do your research, but a big benefit is it is much harder to kill a stapeliad by overwatering.

Pot type

Just like other succulents, stapeliads prefer a compact pot. Potting a small plant up into too large of a pot will cause problems, since more dirt takes longer to dry out, and it will dry unevenly. It's easy to swing from too dry to root rot!

Larger stapeliad variants like Stapelia gigantea and grandiflora will eventually need a pot size of a gallon or more, but cuttings are happy to start out in a 2" pot and work their way up. Smaller spreading types (under 3–4" inch tall) are happy in fairly shallow pots such as bulb pans and bonsai pots.

Different stapeliads have different growth habits: some are columnar, some creeping, some hanging. A lot of stapeliad varieties don't get very tall but are spreaders. The general rule in the plant kingdom is that a plant's roots will be about the size of the plant you see above ground. I find stapeliads loosely follow this rule for depth of roots relative to the plant size, but plants can grow far wider than the roots. A plant will fill a pot and spill over the sides without being at all root-bound so don't be too quick to pot up. Wait until you can see roots trying to grow through holes in the bottom of the pot.

Also beware that wandering stems are liable to root into surrounding pots!

Light

Stapeliads are well-suited as an outdoor plant where I live in Arizona. As natives of Southern Africa, they are well-adapted to heat and bright conditions. Full sun is generally too harsh and will burn the plant. A lot of cacti and succulents adapted to live under larger shrubs and trees, so they are accustomed to filtered light conditions.

Stapeliads thrive in the dappled light under a tree, or shade cloth is another option (30–40% depending on your region). You can place your plants somewhere they get bright indirect light, like a covered porch, but some types need the sun exposure to develop stress coloration.

When experimenting with stapelia as indoors plants, I have had the most success using a grow light. Plants in poorly-lit conditions will struggle and etiolate (stretch out, reaching for light). 

Water

Water regularly in the spring–summer growing season, reduce watering in the late summer and fall, and keep the plant dry over winter. What "regularly" means will depend on your climate! In Arizona I need to water once or twice a week in the growing season.

Take your cue from the plant: if stems are firm, it is hydrated. If stems start to wither and feel almost squishy or spongy, it's getting too dry. Be careful not to overwater your stapeliads by allowing the soil to dry out between waterings. 

I quit watering for the winter when overnight temperatures start to regularly drop below 40–50°F (5–10  °C). Plants with damp roots in colder weather are at risk of succumbing to root rot. This holds true for a lot of ascepliads, including plumeria and adenium.

Overwintering

It’s normal for stapeliads to discolor and shrivel some in their winter state. 

They aren't frost-hardy plants and will need protection over winter. Most varieties are supposed to be hardy to 40–50 °F, but are known to withstand light freezes as long as their soil is dry. I keep my collection in a greenhouse over winter where minimum temperatures don't drop below 40°F.

A lot of stapeliads will survive freezing or near-freezing temperatures outdoors if kept dry. I have observed lovely specimens growing in my neighborhood through the winter in Arizona, but I think they do best in protected "heat pockets" under large trees and next to houses.

It is recommend to not water at all over the winter, but I live in an especially dry climate and do give a light infrequent watering based on how the plants are doing—timing it during a warmer spell to be safe. If they look fine, leave them be! If they seem to be getting too dry, give them water. Just don’t let them stay damp or get cold while the soil is wet.

Fertilizer

You won't need to fertilize until soil nutrients are depleted, so wait several months (depending on how it is planted) for the plant to mature before adding this to the routine.

I use a fertilizer that dissolves in liquid, mixed at half strength, once a month during the growing season. You can use a balanced fertilizer, or one higher in potassium.

Propagation

Virtually all types of stapeliads easily grow from cuttings. They also grow easily from seed, but are notoriously difficult to hand-pollinate. Stapeliads easily hybridize, even across genera, so if plants aren't kept in isolation the seed results can be a gamble. I still save and plant seeds to see if there are any interesting results.

Take cuttings at the base of stems. When your plant matures, I recommend making new cuttings by thinning out dense areas of overlapping branches. It helps deter mealybugs!

Stapeliad cuttings have a very high success rate. I often just plop freshly cut stems on soil and wait. If you want to give your cutting the best chance of survival follow these steps:

• Dip the fresh cutting in rooting hormone and/or horticultural sulfur.
• Allow the cutting to callous.
• Place the cutting flat or at an angle against the top of the soil, NOT poking it straight into the dirt. Stapeliads try to root along their stems wherever they feel the ground.
• Don't water until the cutting begins to develop roots.