Adenia venenata
| Light | Bright light to full sun; a little shade in the fiercest afternoon heat |
|---|---|
| Water | Moderately in active growth; keep dry during the leafless dormant period |
| Soil | Very free-draining mineral mix with extra grit |
| Temperature | Warm-growing; keep well above freezing, roughly USDA zones 10–11 |
| Propagation | Seed; occasionally cuttings |
| Toxicity | Highly toxic — sap and tissues are poisonous to people and pets (see below) |
Adenia venenata is a caudiciform succulent from the dry country of tropical and northeastern Africa and the southwestern Arabian Peninsula, grown for its swollen, bottle-green trunk topped with slender, twining seasonal branches. Its species name — from the Latin for "poisonous" — is a warning worth heeding: the sap and tissues are notably toxic, a trait it shares with much of the genus Adenia.
Description
Adenia venenata builds a stout, smooth caudex that is broadest near the base and tapers upward, often flushed a distinctive grey-green to bluish-green. From the top of this water-storing trunk arise thin, wiry, climbing or scrambling stems that carry the foliage.
The leaves are lobed and more or less palmate, borne on long stalks; they are seasonal, dropping as the plant enters dormancy so that the bare caudex stands alone for part of the year. Like other members of the passionflower family (Passifloraceae), the vining growth can produce tendrils to help it clamber through surrounding scrub. Plants are dioecious, meaning male and female flowers occur on separate individuals; the flowers themselves are small and greenish-yellow, followed on female plants by capsular fruit.
Distribution and habitat
The species has a broad native range across tropical and northeastern Africa, extending from Nigeria eastward to Eritrea and Ethiopia and south to northwestern Tanzania, and across the Red Sea into the southwestern Arabian Peninsula. It is a plant of hot, seasonally arid habitats — savanna, bushland and woodland — where the caudex stores moisture and the deciduous vines exploit the brief growing season before dying back through the long dry months.
Cultivation
Adenia venenata is a rewarding caudiciform for the collector who can respect its rhythm. Grow it warm and bright — it tolerates and even relishes strong sun, which keeps the caudex firm and well-coloured and the vines compact. Use a very open, mostly mineral potting mix and a pot that drains freely; standing wet is the surest way to lose it.
Water moderately while the plant is in leaf and actively growing, letting the mix approach dryness between drinks (see Watering). As the leaves yellow and drop, taper off and keep the plant dry and warm through its dormancy — the bare caudex needs very little until new growth resumes. Many growers raise the caudex progressively at repotting to show it off, though in habitat much of it sits at or below soil level.
Handle with care. All parts contain toxic compounds and an irritant sap; wear gloves when pruning or repotting, keep tools and cuttings away from food surfaces, and site the plant out of reach of children and pets. Wash hands after contact.
Propagation
Seed is the most reliable route and gives the best caudex form; sow onto a warm, gritty surface and keep lightly humid until germination (see Propagation — seed). Cuttings of the vining stems can be taken but tend to root reluctantly and often produce a less shapely, more stem-based plant rather than a true fat caudex. Because the species is dioecious, seed set requires both a male and a female plant in flower. See also Propagation — cuttings.
Common problems
- Rot — the classic caudiciform failure, almost always from overwatering, a heavy mix, or water sitting on the caudex during dormancy. Keep it lean and dry when leafless.
- Soft, etiolated vines — too little light stretches the seasonal growth and pales the caudex; move to a brighter spot.
- Pests — watch for mealybugs tucked into leaf axils and around the growing points, and spider mites in hot, dry, still air. See Pests and diseases.
See also
- Adenia — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — seed · Pests and diseases