Othonna herrei
| Light | Bright light to a few hours of direct sun; a sunny windowsill or lightly shaded greenhouse spot |
|---|---|
| Water | Winter-growing; water while in leaf, keep dry during summer dormancy |
| Soil | Very gritty, fast-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep frost-free; keep cool, airy and dry through summer dormancy; USDA zones ~9b–11 |
| Propagation | Seed (primary); cuttings possible but slow |
| Toxicity | No major toxicity reported; as with other Othonna, best kept away from pets and children |
Othonna herrei is a small, collector's caudiciform succulent from the arid winter-rainfall region of South Africa, prized for its knobbly, warty stem and crown of wavy-margined, blue-green leaves. It is one of the more sculptural members of the genus Othonna, and its gnarled, almost bonsai-like habit makes it a favourite among growers of miniature caudex plants.
Description
Othonna herrei forms a thickened, trunk-like stem (a caudex) that branches with age and is studded with raised, knob-like tubercles — the persistent, woody remains of old leaf bases — giving the plant a rugged, weathered look well beyond its modest size (to about 20–30 cm tall). From the tips of the branches emerges a cluster of fleshy, obovate to spoon-shaped leaves that are a distinctive glaucous blue-green, their margins irregularly toothed and wavy.
Like many winter-growing succulents from the region, it is deciduous: the leaves appear in the cool growing season and are shed as the plant enters summer dormancy, leaving the bare, characterful stem on display. Small yellow, daisy-like flower heads (typical of the family Asteraceae) are carried on slender stalks during the growing period.
Distribution and habitat
The species is a narrow endemic of the Richtersveld in the Northern Cape, South Africa, within the arid, winter-rainfall Succulent Karoo. There it grows on south- and southeast-facing rocky slopes and in sheltered rock crevices, receiving most of its moisture as winter rain and coastal fog while enduring hot, essentially rainless summers. This strongly seasonal climate is the key to understanding its behaviour in cultivation. Its wild range is very small, and the plant is assessed as Vulnerable on South Africa's Red List, threatened chiefly by collectors removing mature plants from habitat — so cultivated material should be seed-grown or nursery-propagated.
Cultivation
The single most important thing to get right with Othonna herrei is its growing rhythm: it is a winter grower. Water it while it is in active growth and leaf through the cooler months, and keep it almost completely dry through its summer dormancy, when watering a leafless, resting plant is the quickest route to rot. Reverse the usual "summer = water" habit of many houseplants and the plant will reward you.
Grow it in a very gritty, sharply draining, mostly mineral mix in a snug pot, and give it plenty of bright light — strong light keeps growth compact and the leaves well coloured, whereas too little produces soft, stretched growth. Good airflow helps prevent fungal problems during the damp growing season. See Watering and Repotting for general technique, and lift the caudex slightly at repotting time if you want to show off its knobbly form.
Propagation
Seed is the usual and most reliable method; sow onto a gritty, well-drained surface and start them into growth in the cool season to match the plant's natural cycle. Cuttings can sometimes be rooted but tend to be slow and less dependable, and cutting-grown plants take time to develop the swollen, characterful stem that makes the species desirable. See Propagation - seed and Propagation - cuttings for full walkthroughs.
Common problems
- Rot — almost always from watering during summer dormancy or from a slow-draining mix; the stem softens and discolours. Keep it dry when leafless.
- Etiolation — insufficient light causes soft, stretched growth and pale, elongated stems.
- Wrong season watering — treating it like a summer grower is the commonest mistake; learn its winter-growing schedule first.
- Pests — mealybugs (white fluff at the leaf bases and on the stem) and the occasional aphid on flower stalks; see Pests and diseases.
See also
- Othonna — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation - seed · Propagation - cuttings