Weberbauerocereus johnsonii
| Light | Full sun to very bright light |
|---|---|
| Water | Moderate in the growing season; keep dry and cool in winter |
| Soil | Fast-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; best in USDA zones 9b–11 |
| Propagation | Seed; stem cuttings |
| Toxicity | Non-toxic to cats and dogs |
Weberbauerocereus johnsonii is a spiny, columnar cactus from Peru, grown for its tall upright habit and the dense, handsome spination that clothes its ribbed green stems. Like others in the genus Weberbauerocereus, it is a robust cactus of arid Andean Peru, valued in collections as much for its striking spines as for its eventual stature.
Description
Weberbauerocereus johnsonii is an erect, columnar cactus that branches from the base or low on the stem, forming clustering, tree-like clumps with age. The green to grey-green stems are ribbed and closely set with areoles, from which emerge numerous stiff spines. The spination is dense and variable in colour, often shading from pale golden to amber or brownish, and it is this generous covering — rather than any single striking feature — that gives the plant its ornamental appeal.
Mature plants can flower, producing tubular, night-opening blooms typical of the genus, borne toward the stem tips. As with most columnar cacti, flowering comes only once a plant has reached a good size and age.
Distribution and habitat
The species is native to Peru, where it has been recorded from the Cajamarca and Ancash regions, growing on arid, rocky slopes and in dry inter-Andean valleys at higher elevations. Plants of this habitat endure strong sun, sharp drainage and long dry spells, drawing on infrequent seasonal rain. These conditions are the key to understanding its care: it is adapted to brightness and drought, not to rich, moisture-retentive soil.
Cultivation
W. johnsonii is an undemanding grower given the two things it most needs — strong light and excellent drainage. Plant it in a very free-draining, mostly mineral mix and give it the brightest position available; abundant light keeps the stems compact and the spines strong and well-coloured. Water moderately through the warm growing season, always letting the mix dry out before watering again, then keep the plant dry and cool over winter to prevent rot and encourage sturdy growth.
Being a vigorous columnar species, it appreciates room for its roots and benefits from occasional repotting as it fills its container. Protect it from frost; while it tolerates cool, dry winters, wet cold is a common cause of loss. See Watering for general technique.
Propagation
The species is grown both from seed and from stem cuttings. Seed is sown on a warm, gritty surface kept lightly humid until the seedlings establish (see Propagation — seed). Cuttings of the columnar stems can also be taken: allow the cut surface to callus and dry for a period before setting the piece in a dry, mineral mix to root (see Propagation — cuttings). Columnar cacti like this are also sometimes used as vigorous rootstock for grafting.
Common problems
- Rot — the usual cause of loss, brought on by overwatering, a slow-draining mix, or wet, cold winter conditions.
- Etiolation — too little light makes the stems thin, pale and weakly spined, spoiling the plant's characteristic dense spination.
- Pests — mealybugs (white fluff in the areoles) and red spider mites (fine webbing, bronzed skin) are the most common; watch the crowded areoles where they can hide among the spines.
See also
- Weberbauerocereus — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed · Propagation — cuttings · Repotting · Pests and diseases