Nananthus vittatus
| Light | Bright light to full sun; the more light, the tighter and more colourful the growth |
|---|---|
| Water | In the cool growing season (autumn to spring); keep dry through summer dormancy, and during hard winter frost |
| Soil | Very gritty, fast-draining mineral mix (see Soil and potting mix) |
| Temperature | Exceptionally cold-hardy for a mesemb: tolerates hard frost to about −12 °C (10 °F) when kept dry; USDA zones 7–10 |
| Propagation | Seed (primary); division of clumps |
| Toxicity | Not known to be toxic to cats or dogs |
Nananthus vittatus is a small, clump-forming caudiciform mesemb from the grasslands of South Africa, grown above all for its swollen, woody taproot. Left partly exposed above the soil, that fat root gives the plant the look of a miniature bonsai, topped with rosettes of stiff, tubercled leaves and cheerful yellow flowers finely striped with brownish or reddish lines. It belongs to the genus Nananthus, a group of dwarf, hardy members of the ice-plant family Aizoaceae.
Description
Nananthus vittatus grows from a thick, tuberous taproot that stores water and, in cultivation, is usually lifted proud of the soil to be admired. From the crown of this root arise one to several small rosettes of firm, upright to spreading leaves. The leaves are roughly triangular in cross-section, keeled beneath, and their upper surfaces are rough, dotted with small raised tubercles. The epithet vittatus means "striped" or "banded"; the striping is most evident in the fine reddish line down each petal of the flower.
The whole plant is low and slow, rarely more than a few centimetres tall above the caudex, though the root itself can thicken considerably over many years. Flowers appear from the centre of the rosettes, chiefly in late winter and early spring, opening in bright sun: they are daisy-like (as in all mesembs, not true daisies) and yellow, with each petal marked by a fine reddish-brown median stripe. As with most of its relatives, the blooms close again toward evening and in dull weather.
Distribution and habitat
The species occurs in the interior of South Africa, in the south-eastern Northern Cape and the adjoining North West Province — the latter part of the old Transvaal, a heritage preserved in its synonym Nananthus transvaalensis. There it grows on plains and gentle slopes in fine, lime-rich (calcareous) loams, often among grasses, in a region of hot, dry summers and cold, frosty, largely winter-rainfall winters. In habitat the bulk of the plant sits below ground, with only the leaf rosettes showing at the surface; the ornamental "exposed caudex" seen in collections is a horticultural convention rather than the wild habit.
Cultivation
Nananthus vittatus is an undemanding little plant that rewards restraint. Grow it in a deep pot to accommodate the taproot, in a very free-draining, mostly mineral mix, in bright light or full sun. Strong light keeps the rosettes compact and encourages flowering; too little light produces soft, stretched growth.
This is a cool-season grower: it is active from autumn through spring and rests in the heat of summer. Water through the cool growing months whenever the mix is not frozen, always letting it dry out between waterings, and keep the plant dry and shaded through the peak of summer, when it is dormant. The species is exceptionally cold-hardy for a mesemb — reportedly to around −12 °C — provided it is bone dry, so in climates with freezing winters simply withhold water during hard frosts rather than trying to keep it warm. Overwatering — especially in warm, stagnant conditions — is the main cause of rot; see Watering and Repotting for general technique.
Many growers gradually raise the caudex over successive repottings, exposing a little more of the root each time so the plant develops its prized bonsai-like form.
Propagation
Seed is the usual and most reliable method. Sown on a gritty, mineral surface and kept warm and lightly moist, the seed germinates readily, and seedlings develop their characteristic thickened root early. Established clumps that have formed multiple heads can also be lifted and divided, taking care to preserve roots on each division. See Propagation — seed and Propagation — offsets for fuller walkthroughs.
Common problems
- Rot — the commonest cause of loss, almost always from overwatering, a poorly draining mix, or watering during the summer dormancy or a hard winter freeze; the caudex softens and discolours.
- Etiolation — too little light makes the leaves elongate and the rosettes open up, spoiling the tight form.
- Pests — mealybugs can hide among the leaf bases and on the roots, and root mealybugs in particular are worth checking for at repotting. See Pests and diseases.
See also
- Nananthus — the genus overview
- Mesemb — the wider ice-plant group
- Soil and potting mix · Watering · Repotting · Propagation — seed