Tylecodon wallichii
| Light | Bright light; full sun in cooler months, some shade from intense summer heat |
|---|---|
| Water | Winter-grower — water in the cool season, keep dry through summer dormancy |
| Soil | Very free-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep frost-free; USDA zones 9b–11 |
| Propagation | Seed; stem or branch cuttings taken in the growing season |
| Toxicity | Toxic — contains bufadienolides; keep away from pets and livestock |
Tylecodon wallichii is a caudex-forming succulent shrublet from the winter-rainfall regions of South Africa, distinctive for the knobby, grey stem left behind when its leaves drop. As each season's cylindrical leaves fall away, their swollen bases persist as woody tubercles (technically phyllopodia), studding the stem and giving the plant its wonderfully gnarled, warty appearance. It belongs to the genus Tylecodon, a group of deciduous, winter-growing relatives of Cotyledon.
Description
Tylecodon wallichii forms a squat, succulent-stemmed shrublet, typically reaching a few tens of centimetres tall (occasionally more), with a thickened basal caudex and short, chunky branches. The most striking feature is the surface of the stems: covered in persistent, pointed leaf-base tubercles that remain long after the leaves themselves have withered and fallen, so that even a bare, dormant plant looks textured and sculptural.
The leaves are narrow, cylindrical to club-shaped, soft and green, clustered near the branch tips during the growing season. They are deciduous, dropping as the plant enters summer dormancy. The plant produces tubular, greenish-yellow flowers on slender, branching stalks that rise well above the stems, nodding at the tips in the manner typical of the genus.
Distribution and habitat
The species is native to the arid winter-rainfall zone of South Africa, in the Northern and Western Cape, extending into the Karoo and Namaqualand fringe. It grows on rocky slopes and flats in low, open scrub, where it receives moisture in the cool winter months and endures hot, dry summers. This winter-growing, summer-dormant rhythm is fundamental to understanding it in cultivation.
Cultivation
Tylecodon wallichii is grown for its characterful, tubercled stems and undemanding nature, but it must be treated as a winter grower: it wakes and leafs out as temperatures fall in autumn, grows through winter, and drops its leaves to rest through summer. Water regularly (letting the mix dry between soakings) during the cool growing season, and keep it nearly bone-dry once the leaves yellow and fall — summer water on a dormant plant is the quickest route to rot.
Grow it in a very free-draining, mostly mineral mix in a pot with ample drainage, in bright light. It appreciates strong sun in the cooler growing months, with a little shade from the fiercest summer heat. Protect from frost. See Watering and Repotting for general technique, and note the plant's toxicity when siting it around pets or children.
Propagation
The species is readily raised from seed sown at the start of the cool season onto a gritty, mineral surface kept lightly moist. It can also be grown from stem or branch cuttings taken during active growth: allow the cut end to callous for a few days, then set it in a dry, gritty mix and water sparingly until roots form. Cuttings are the simplest way to keep a form true.
Common problems
- Summer rot — by far the commonest cause of loss; watering a dormant, leafless plant in summer softens the caudex and stems. Keep it dry when at rest.
- Etiolation — too little light stretches the stems and spaces out the tubercles, losing the compact, gnarled look.
- Pests — mealybugs (white fluff in leaf axils and on roots) are the usual nuisance; watch also for aphids on the soft new growth and flower stalks. See Pests and diseases.
Toxicity
Like a number of Tylecodon and Cotyledon species, T. wallichii contains toxic bufadienolides and is poisonous. In its native range it is notorious among stock farmers for causing krimpsiekte ("shrinking disease"), a serious, often fatal poisoning of grazing animals in which the cumulative neurotoxic compounds build up in the body. It is handsome as an ornamental but is genuinely toxic: keep it away from pets, livestock and children, and handle it as a strictly non-edible collector's plant.
See also
- Tylecodon — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — seed · Propagation — cuttings · Pests and diseases