Coryphantha elephantidens subsp. greenwoodii
| Light | Bright light with some protection from the fiercest afternoon sun |
|---|---|
| Water | Moderate in growth; allow to dry fully between waterings, keep dry in winter |
| Soil | Fast-draining mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; roughly USDA zones 9b–11 |
| Propagation | Seed; occasional offsets |
| Toxicity | Non-toxic to cats and dogs |
Coryphantha elephantidens subsp. greenwoodii is a subspecies of the large-bodied Mexican cactus Coryphantha elephantidens. It is known from a restricted area in the Mexican state of Oaxaca and, like the species as a whole, is grown for its large, showy flowers.
Description
Like the parent species, C. elephantidens subsp. greenwoodii forms a mostly solitary, blue-green to grey-green globe built from large, blunt tubercles — the fat, rounded projections that give the species its "elephant tooth" nickname. Woolly areoles sit in the axils between the tubercles, and stout, curved spines radiate from the tips. Plants are slow-growing and can become substantial, weighty specimens with age.
Large, silky blooms open from the woolly crown in late summer. As in the species, they are borne in pink to magenta tones. As with most Coryphantha, the flowers open over a succession of warm, bright days.
Distribution and habitat
Coryphantha elephantidens is native to central and southern Mexico, where it grows in seasonally dry scrub and grassland, often rooting among rocks and low vegetation that provide light shade. This subspecies is known from a restricted part of that range in Oaxaca. As with all cacti, the genus is listed under CITES Appendix II; nursery-propagated plants are legal to own and trade, while collecting from the wild is not.
Cultivation
Cultivation follows the parent species, Coryphantha elephantidens. Grow it in a very free-draining, mostly mineral mix in bright light, giving a little shade from the most intense afternoon sun. Water thoroughly during the warm growing season once the soil has dried out, then allow it to dry again before the next watering. Keep the plant dry and cool through winter — this winter rest both prevents rot and encourages the following season's flowers.
Because the species is naturally slow and builds a fleshy, water-storing body, overwatering is the most common cause of loss. See Watering and Repotting for general technique.
Propagation
Seed is the usual method. Sow on a warm, mineral surface kept humid until germination. Mature plants may occasionally produce offsets, which can be separated and rooted, though the species is more often solitary. See Propagation — seed and Propagation — offsets for full walkthroughs.
Common problems
- Rot — almost always from overwatering or a slow-draining mix, especially during the cool months; the body softens and discolours from the base.
- Etiolation — too little light makes the body pale and pushes weak, elongated growth that loses the compact form.
- Pests — mealybugs (white fluff in the woolly areoles) and root mealybugs are the usual culprits, with red spider mites a risk in hot, dry air. See Pests and diseases.
See also
- Coryphantha — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — seed · Propagation — offsets