Haworthia retusa
| Light | Bright, indirect light; avoid harsh, direct midday sun |
|---|---|
| Water | Moderately in growth; let the mix dry out between waterings, reduce watering in winter |
| Soil | Gritty, fast-draining mix (see Soil and potting mix) |
| Temperature | Keep above freezing; USDA zones 9b–11 |
| Propagation | Offsets; leaf cuttings; seed |
| Toxicity | Non-toxic to cats and dogs |
Haworthia retusa is a robust, low-growing rosette succulent from the Western Cape of South Africa, prized for its thick triangular leaves that bend sharply backward to present flat, translucent "windowed" upper faces to the sky. Those glassy leaf-tips — the source of the name retusa, meaning "blunted" or "turned back" — let light filter down into the plant, and give the species its charmingly geometric, almost architectural look. It belongs to the Haworthia genus and is sometimes sold under the trade name star cactus, though it is neither a star nor a cactus.
Description
Haworthia retusa forms a stemless rosette, usually solitary in habitat but readily offsetting into small clumps in cultivation. The leaves are fleshy and stiff, triangular in cross-section, and recurve strongly so that the flattened, near-translucent upper surface — the "window" or fenestra — faces upward. These windows are typically marked with pale longitudinal lines and a faint reticulate pattern, and the leaf colour ranges from fresh green to a coppery or reddish tone when grown in bright light.
Mature rosettes commonly reach around 8–12 cm across. In late spring and summer the plant sends up a slender flowering stem (an inflorescence) bearing small, tubular white flowers striped with green or brown — modest blooms typical of the genus, where the foliage is very much the main event.
Distribution and habitat
The species is a narrow endemic of the Western Cape province of South Africa, centred on the Riversdale district (roughly Heidelberg to Riversdale), where it grows on clayey hills in seasonally dry scrub, often nestled under low bushes and among stones. In habitat plants frequently sit low in the ground with only the retused leaf-tips exposed, an arrangement that protects the body from heat and grazing while the windowed faces gather light. Rainfall is seasonal, so wild plants experience distinct wet growth periods and prolonged dry rests.
Cultivation
Haworthia retusa is an accommodating, beginner-friendly succulent that asks mainly for restraint with the watering can. Grow it in a gritty, free-draining mix in a pot that isn't too large, and give it bright, indirect light — an east or lightly shaded window is ideal. Too little light causes the rosette to stretch and pale; very harsh direct sun can scorch or bronze the windows, though a little colour stress is prized by many growers.
Water moderately once the soil has dried out during the active growing seasons (typically spring and autumn), and keep the plant considerably drier through the heat of high summer and during cold winter spells, when growth slows. Overwatering and slow-draining soil are the usual causes of loss. See Watering and Repotting for general technique.
Propagation
H. retusa is easily increased. Established clumps can be divided, lifting rooted offsets away from the parent when repotting. Healthy leaves can also be removed cleanly and set as leaf cuttings, though haworthia leaves root more reluctantly than those of many other succulents, so patience helps. The species also comes true enough from seed, which is how larger batches and new selections are raised.
Cultivars
Haworthia retusa and its close relatives have been selected for larger windows, bolder patterning and more compact form. Choice clones and the giant-growing forms sometimes grouped under names like H. retusa 'Giant' are popular with collectors, and the species features in many intra-generic hybrids. Because the boundaries within this group are fluid, some plants sold as H. retusa may belong to closely allied taxa such as H. turgida.
Common problems
- Rot — almost always from overwatering or a mix that stays wet; the rosette softens and browns from the base.
- Etiolation — too little light makes leaves elongate, thin and pale, and the rosette loses its tight form.
- Scorch — sudden intense sun can bleach or brown the leaf windows; acclimatise plants gradually.
- Pests — mealybugs (white fluff between the leaves and at the roots) and, less often, root aphids are the main nuisances (see Pests and diseases).
See also
- Haworthia — the genus overview
- Soil and potting mix · Watering · Repotting
- Propagation — offsets · Propagation — cuttings · Propagation — seed
- Pests and diseases