Haworthiopsis viscosa
| Light | Bright light to light shade; tolerates less light than many succulents |
|---|---|
| Water | Moderately in growth; let the soil dry between waterings, keep drier in winter |
| Soil | Gritty, free-draining mix (see Soil and potting mix) |
| Temperature | Keep above freezing; protect from frost, USDA zones 9b–11 |
| Propagation | Offsets and cuttings; also seed |
| Toxicity | Non-toxic to cats and dogs |
Haworthiopsis viscosa is a clumping South African succulent whose stiff, triangular leaves are stacked in three neat vertical ranks, building slender dark green columns that lean and cluster into dense colonies. The tidy, geometric leaf arrangement — three-ranked and column-forming — makes it one of the most recognisable members of the genus Haworthiopsis and a longtime favourite of collectors who love its architectural form.
Description
Haworthiopsis viscosa grows as an erect or gently sprawling stem clothed in firm, incurved, triangular leaves arranged in three distinct rows (the tristichous, or three-ranked, habit that gives the plant its distinctive tower-like outline). Each leaf is dark green — often flushing bronze, purplish or almost blackish in strong light — with a rough, slightly sticky-looking surface; the old species name viscosa ("sticky") nods to this texture, though the leaves are not truly tacky to the touch.
Individual stems reach roughly 10–20 cm tall over time and offset freely from the base, so a happy plant slowly builds a congested clump of leaning columns rather than a single rosette. Like other members of the genus it sends up a slender flowering stalk bearing small, tubular, greenish-white to brownish flowers — modest compared with the foliage, which is very much the point of the plant.
Distribution and habitat
The species is native to South Africa, where it is widespread across the arid interior of the Eastern and Western Cape, extending into the Karoo. It grows in very well-drained, often sandy or rocky soils, either in full sun or in the partial shelter of a bush or rock crevice. This is a tough, variable plant across its range, and several forms and former "species" are now folded into it.
Cultivation
Haworthiopsis viscosa is an easy, forgiving houseplant and an excellent choice for beginners. Grow it in a gritty, free-draining mix in a pot that drains well, and give it bright light to light shade — it colours up handsomely in strong light but, unlike many desert cacti, also copes with the lower light of an indoor windowsill, merely staying greener and more open.
Water moderately while the plant is in active growth, letting the mix dry out between waterings, and cut back in winter to keep it on the dry side. The commonest cause of trouble is overwatering in cold conditions, which rots the base. See Watering and Repotting for general technique. Because it clumps enthusiastically, it appreciates dividing and refreshing every few years.
Propagation
The easiest method is division: lift a clump and separate the rooted offsets, letting any cut surfaces callus before potting. Individual stems or stem sections also strike readily as cuttings once callused. The species can be raised from seed as well, though vegetative methods are quicker and keep desirable forms true.
Common problems
- Rot — from overwatering, a poorly draining mix, or water sitting in the crowded clump during cold weather; stems soften and blacken from the base.
- Etiolation — in too little light the columns stretch, the leaves space out and the neat three-ranked geometry is lost.
- Pests — mealybugs (white fluff between the tightly packed leaves and at the roots) are the main nuisance; watch also for fungus gnats in soggy mixes. See Pests and diseases.
See also
- Haworthiopsis — the genus overview
- Soil and potting mix · Watering · Propagation — offsets · Propagation — cuttings · Repotting