Myrtillocactus cochal
| Light | Bright light to full sun once established |
|---|---|
| Water | Sparingly; let the mix dry out fully between soakings, keep dry in winter |
| Soil | Fast-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; USDA zones 9b–11 |
| Propagation | Seed or stem cuttings |
| Toxicity | Non-toxic to cats and dogs |
Myrtillocactus cochal is a shrubby, tree-like candelabra cactus native to the Baja California peninsula of Mexico, where it forms dense, many-branched stands of blue-green stems armed with short, dark spines. Known locally as the cochal, it is a close relative of the more familiar Myrtillocactus geometrizans and shares the genus's characteristic frosted, waxy stem colour and branching, candelabra habit.
Description
Myrtillocactus cochal grows as a large, freely branching shrub or small tree, typically developing a short woody trunk from which numerous erect and arching stems radiate to form a broad, candelabra-shaped crown. Mature plants can reach the size of a substantial shrub in habitat. The stems are blue-green to grey-green, often with a fine waxy bloom, and are divided into several low, rounded ribs.
The areoles carry short, stout spines that are dark — blackish to grey — giving the plant a noticeably darker-armed look than its blue-stemmed relatives. Small, pale flowers appear along the upper ribs, followed by small rounded fruits. As with other Myrtillocactus, several flowers may open from a single areole, an unusual trait for a cactus.
Distribution and habitat
The species is more or less endemic to the Baja California peninsula, growing on rocky slopes, hillsides and coastal scrub in the dry, warm conditions typical of the region. There it is often a conspicuous component of the desert vegetation, forming thickets alongside other columnar cacti and drought-adapted shrubs. Its natural range experiences low, seasonal rainfall, considerable heat and excellent drainage — conditions worth keeping in mind in cultivation.
Cultivation
Like the rest of the genus, Myrtillocactus cochal is a fairly easy and vigorous grower where it can be kept warm and dry in winter. Give it a very free-draining, mostly mineral mix and a position in bright light; young plants appreciate a little shade from the most intense sun, but established plants take full sun well and colour up best there.
Water thoroughly during the warm growing season once the mix has dried out, then allow it to dry again before the next soaking. Reduce watering sharply as temperatures fall and keep the plant dry through winter, as cold combined with damp is the quickest route to rot. It is sensitive to hard frost and is best grown under cover or indoors in bright light where winters are cold. See Watering and Repotting for general technique.
Propagation
M. cochal can be raised from seed or grown from stem cuttings. Cuttings root readily: take a healthy stem section, allow the cut surface to callus over for a week or two in a dry, shaded spot, then set it in a barely-moist mineral mix until roots form. Seed is sown on a warm, gritty surface kept lightly humid. Because of its vigour, the species is also sometimes used as grafting stock for slower or more delicate cacti. See Propagation — cuttings and Propagation — seed for full walkthroughs, and Grafting for its use as rootstock.
Common problems
- Rot — nearly always from overwatering, a slow-draining mix, or cold wet conditions in winter; stems soften and discolour, often from the base.
- Cold damage — frost scars the stems and can kill unprotected plants; keep above freezing.
- Pests — mealybugs (white fluff in the areoles and at the roots) and scale are the usual offenders; watch also for red spider mites in hot, dry, still air. See Pests and diseases.
See also
- Myrtillocactus — the genus overview
- Myrtillocactus geometrizans — the widely grown relative
- Grafting · Soil and potting mix · Watering · Propagation — cuttings · Propagation — seed