Stapelia gigantea
| Light | Bright light with some shade from harsh midday sun; tolerates more shade than most cacti |
|---|---|
| Water | Moderate in warm growth; let the mix dry between waterings, keep drier and cooler in winter |
| Soil | Fast-draining, gritty mix (see Soil and potting mix) |
| Temperature | Warmth-loving; keep above about 10 °C, best in USDA zones 9b–11 |
| Propagation | Stem cuttings (easy); seed |
| Toxicity | Generally regarded as non-toxic; the sap is clear and watery (not the milky latex of some relatives), but discourage pets from chewing the stems |
Stapelia gigantea, the Zulu giant, is a clump-forming stem succulent from southern Africa that produces some of the largest flowers of any stapeliad. Its huge, star-shaped blooms are pale ochre to buff, heavily wrinkled, red-lined and fringed with soft hairs, and — like other members of the group — they mimic carrion to attract pollinating flies, earning the plant the common name giant toad plant. It belongs to the genus Stapelia.
Description
Stapelia gigantea forms low, spreading clumps of erect, four-angled green stems, usually 15–30 cm tall, softly toothed along the angles and velvety to the touch. The stems are spineless and fleshy, branching from the base to build up a broad, cushion-like mat over time.
The flowers are the plant's showpiece. Opening from large, pointed, balloon-like buds, they flatten into shallow five-pointed stars that can span well over 20 cm across in a strong plant — among the biggest in the whole succulent world. The surface is pale yellow to ochre, finely wrinkled and marked with fine crimson transverse lines, and the margins carry a fringe of long, soft purplish hairs. As with the rest of the genus, the open blooms give off a strong smell of decay that draws in blowflies and other flies as pollinators, a strategy known as sapromyiophily.
Distribution and habitat
The Zulu giant is native to a broad swathe of southern and southeastern Africa, including South Africa, Zimbabwe, Mozambique, Malawi and neighbouring regions. It grows in warm, seasonally dry bushveld and grassland, typically sheltering among rocks, low shrubs and grass tufts that shade its roots and stem bases. This habitat gives a good guide to cultivation: warmth, bright but broken light, and soil that never stays wet.
Cultivation
Stapelia gigantea is one of the easiest and most rewarding stapeliads for beginners, and more forgiving of shade than most cacti. Grow it in a very free-draining, gritty mix in a wide, shallow pot that gives the clump room to spread. Give it bright light with protection from the fiercest midday sun; too much harsh sun scorches and reddens the stems, while too little makes them thin and floppy.
Water moderately through the warm growing season, always letting the mix dry out before watering again, and cut back sharply in winter to keep the plant cool and nearly dry. The soft stems rot readily if kept cold and wet, so winter dryness is the key to success. See Watering and Repotting for general technique.
Propagation
Propagation is very easy from stem cuttings. Detach a healthy segment, let the cut surface dry and callus for several days, then set it on or just into a gritty mix; rooting is usually quick in warm conditions. Fresh seed also germinates readily, though seed-grown plants take longer to reach flowering size and named characteristics are best kept true by cuttings. See Propagation — cuttings and Propagation — seed for full walkthroughs.
Common problems
- Stem rot — the most common killer, almost always from a cold, wet winter or a slow-draining mix; affected stems turn soft, yellow and mushy. Remove rotted portions promptly and re-root any clean pieces.
- Sunburn — harsh, unfiltered sun can scorch or redden the soft stems; give light shade in the hottest months.
- Pests — mealybugs (white fluff in the crevices and roots) and, in dry indoor air, spider mites are the usual troublemakers. See Pests and diseases.
- The smell — the flowers are pollinated by flies and stink of carrion when open; site a flowering plant where the odour, and the flies it attracts, won't be a nuisance indoors.
See also
- Stapelia — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — cuttings · Pests and diseases