Monadenium schubei
| Light | Bright light to light shade; strong light deepens colour |
|---|---|
| Water | Regularly in growth, sparingly; keep nearly dry when leafless in winter |
| Soil | Fast-draining gritty mix (see Soil and potting mix) |
| Temperature | Warmth-loving; keep above about 10 °C, USDA zones 10–11 |
| Propagation | Stem cuttings (easy); also seed |
| Toxicity | Caustic milky sap — irritant to skin, eyes and mouth; keep away from pets and children |
Monadenium schubei is a clump-forming succulent euphorb from East Africa, grown for its knobbly, tuberculate stems and, above all, for the popular dark-coloured selection sold as 'Tanzania Red'. Like the rest of the genus it is now often treated botanically within Euphorbia, but growers and collectors still know it best under its familiar Monadenium name.
Description
Monadenium schubei forms clustering, cylindrical stems that branch mainly from the base and grow more or less erect, reaching around half a metre or more in cultivation over time. The stems are patterned with spirally arranged, low conical tubercles, giving the surface a distinctly warty, textured look. The leaves are soft and fleshy, carried toward the growing tips and shed as the plant goes dormant.
The species is best known for its coloured forms. In the widely grown 'Tanzania Red' selection both the stems and the foliage flush a deep burgundy to near-purple, especially in strong light. As with all Monadenium, the small flower-like structures (cyathia) are enclosed in a shield-like bract — the trait that distinguishes the genus — and appear near the stem tips.
Like other members of the family, the plant carries a milky white latex that is caustic and irritating; handle it with care and wash off any sap promptly.
Distribution and habitat
Monadenium schubei is native to East Africa, in the region of Tanzania and neighbouring areas, where it grows in seasonally dry woodland and scrub. In habitat it experiences a warm growing season with summer rains followed by a dry, cooler rest, and it typically roots in gritty, free-draining ground with some shade from surrounding vegetation.
Cultivation
This is an easy and rewarding succulent for a warm, bright spot. Grow it in a fast-draining, gritty mix and water regularly through the warm growing season, letting the mix dry between waterings. As the plant slows and drops its leaves in autumn, reduce water sharply and keep it nearly dry and warm through winter — cold, wet roots are the main cause of loss. See Watering and Repotting for general technique.
Give it plenty of light: bright conditions keep the growth compact and, in 'Tanzania Red', bring out the richest colour. In too little light the stems stretch and the colour fades toward plain green.
Take the usual precautions with the caustic sap when pruning or repotting — wear gloves, keep it away from your eyes, and keep the plant out of reach of pets and children.
Propagation
Stem cuttings are the simplest method and root readily. Cut a stem section, rinse or blot away the bleeding latex, and allow the cut end to dry and callus for several days before setting it in a dry, gritty mix and watering lightly once roots begin. The species can also be raised from seed. See Propagation — cuttings for a full walkthrough.
Cultivars
- 'Tanzania Red' — by far the most commonly grown form, selected for dark burgundy to purplish stems and foliage that colour best in strong light. Its care is exactly as for the species above.
Common problems
- Rot — from overwatering, a poorly draining mix, or water sitting on the plant while cold; stems soften and discolour, usually from the base.
- Etiolation — insufficient light causes weak, stretched stems and loss of the deep colour.
- Pests — mealybugs (white fluff in the leaf axils and roots) and spider mites are the usual offenders; see Pests and diseases.
See also
- Monadenium — the genus overview
- Euphorbia — the genus into which Monadenium is often merged
- Propagation — cuttings · Soil and potting mix · Watering · Repotting · Pests and diseases