Copiapoa humilis
| Light | Bright light with good airflow; some protection from the fiercest afternoon sun |
|---|---|
| Water | Sparingly in the warmer months; keep dry through the cool winter rest |
| Soil | Very free-draining, mostly mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; happiest in cool, dry, bright conditions |
| Propagation | Seed, or division of established clumps and offsets |
| Toxicity | Non-toxic to cats and dogs |
Copiapoa humilis is a small, freely clustering cactus from the coastal deserts of northern Chile, and one of the easiest and most forgiving members of the genus Copiapoa to grow. It forms low mounds of soft-bodied, greyish to olive-green heads anchored by a stout tuberous root, and produces cheerful yellow flowers with relatively little fuss — which is why it is so often recommended as a beginner's introduction to a group that has a reputation for being slow and demanding.
Description
Copiapoa humilis is a dwarf, clumping species. Individual heads are small — usually only a few centimetres across — and dark green to greyish or slightly brownish, becoming more heavily patina'd in strong light. The plants sit above a thickened, tuberous taproot that stores water and helps them ride out long dry spells; this root is often larger than the visible body above ground.
The ribs are low and broken into tubercles, each carrying an areole with fine, dark, bristly spines that are modest compared with the fierce armament of some relatives. Over time a single plant offsets steadily from the base to build up a low cushion of many heads. Flowers appear from near the crown in the warmer months: funnel-shaped and bright yellow, opening in sunshine, and produced quite willingly on healthy plants.
Distribution and habitat
Like the rest of the genus, C. humilis is native to the arid coastal belt of northern Chile, in the Atacama Desert. There the plants grow on rocky, mineral ground in a landscape that receives almost no conventional rainfall, drawing much of their moisture from the ocean fogs (the camanchaca) that roll in off the Pacific. The tuberous root and clustering habit are both adaptations to this fog-fed, drought-prone environment.
Wild Copiapoa populations are slow-growing and vulnerable to habitat disturbance and illegal collection, and — like the whole cactus family — the genus is listed under CITES. Nursery-raised plants are widely available and are the only ones that should be bought or traded; collecting from habitat is neither necessary nor lawful.
Cultivation
Copiapoa humilis is among the most beginner-friendly of the copiapoas because it is faster and more tolerant than many of its relatives. Grow it in a very free-draining, mostly mineral mix in a pot deep enough to accommodate the tuberous root, and give it bright light with good air movement. A little shade from the harshest afternoon sun helps prevent scorching, but too little light leads to soft, etiolated growth.
Water thoroughly during the active growing season once the soil has dried out, then allow it to dry again before the next watering. Through the cool months keep the plant dry and rested — copiapoas resent winter wet, and cold damp soil is the quickest way to lose the tuberous root to rot. See Watering and Repotting for general technique.
Propagation
The species can be raised from seed, which germinates readily on a warm, mineral surface kept lightly humid (see Propagation — seed). Because it clusters so freely, it is also easily increased by division: established clumps can be split, or rooted heads and offsets taken from the base, allowed to callus, and potted into a gritty mix. This makes it simple to share and to build up a good-sized specimen.
Common problems
- Rot — almost always from overwatering, winter wet, or a poorly draining mix; the tuberous root and lower heads soften and discolour.
- Etiolation — too little light produces pale, elongated heads that lose the compact, patina'd look of well-grown plants.
- Pests — mealybugs (white fluff among the heads and on the roots) and red spider mites are the usual offenders; check the root zone at repotting time. See Pests and diseases.
See also
- Copiapoa — the genus overview
- Soil and potting mix · Watering · Repotting
- Propagation — seed · Propagation — offsets
- Pests and diseases