Mammillaria marksiana
| Light | Bright light with some protection from the harshest afternoon sun |
|---|---|
| Water | Regularly in the growing season, letting the mix dry between waterings; keep dry in winter |
| Soil | Fast-draining mineral-rich mix (see Soil and potting mix) |
| Temperature | Keep above freezing; USDA zones 9b–11 |
| Propagation | Seed; occasionally offsets |
| Toxicity | Non-toxic to cats and dogs |
Mammillaria marksiana is a green, globular cactus from western Mexico, prized for the abundant snow-white wool that gathers in its axils and crown, set against clusters of short, golden-yellow spines. In late winter to spring it rings its apex with greenish- to lemon-yellow flowers. It is an easy but slow-growing member of the large genus Mammillaria.
Description
Mammillaria marksiana forms a solid, flattened-globular to shortly cylindrical body, usually solitary. The green surface is arranged into firm, conical, weakly four-sided tubercles, and it is between these tubercles, in the axils, that the plant produces its characteristic abundant white wool. Fresh wool concentrates most densely at the growing point and through the flowering zone, framing the crown.
The spines are short — roughly 5–8 mm — and needle-like, golden-yellow to brown, radiating from white-felted areoles at the tubercle tips; their number is variable. Because the spines are short, it is the dense wool rather than the spines that dominates the plant's appearance, so it reads as a woolly, white-and-gold cushion rather than a fiercely spiny one. Older plants may cluster by producing offsets, building up small groups over many years.
Flowers appear in a ring around the crown, typically from late winter into spring. They are small, funnel-shaped and green to lemon-yellow, and are followed by the small, club-shaped fruit typical of the genus. As with most Mammillaria, the blooms open over a succession of days rather than all at once.
Distribution and habitat
The species is native to western Mexico, in the states of Sinaloa and Durango, where it grows on rocky slopes and in gritty, well-drained ground within thornscrub and dry woodland. In habitat it experiences a warm growing season with summer rains and a distinctly dry, cool winter rest — the pattern most growers aim to imitate in cultivation.
Cultivation
Mammillaria marksiana is an easy and free-flowering cactus, though slow-growing and reputedly prone to rot if kept wet or cold. Grow it in a gritty, free-draining, mostly mineral mix in a pot that is not too oversized, and give it bright light with a little shade from the fiercest afternoon sun; strong light keeps the body compact.
Water thoroughly through the warm months once the mix has dried, then reduce watering sharply as autumn arrives; avoid watering over the top of the plant, as water trapped in the wool can spoil it and encourage rot. Keep the plant dry and cool over winter — this winter rest both protects against rot and helps trigger the spring flush of flowers. Reputedly sensitive to cold, it copes best when kept dry before and during cold spells. See Watering and Repotting for general technique, and take care never to leave the plant standing in wet, airless compost.
Propagation
Seed is the usual and most reliable method: sow onto a warm, damp, mineral surface and keep humid until germination, then grow the seedlings on gradually. Where established plants have produced offsets, these can be removed and rooted as a quick vegetative route. See Propagation — seed and Propagation — offsets for full walkthroughs.
Common problems
- Rot — the commonest cause of loss, almost always from overwatering, a slow-draining mix, or water sitting in the wool and crown; the body softens and discolours from the base or centre.
- Etiolation — too little light makes the body pale and stretch upward, and the plant produces less of its characteristic dense wool.
- Pests — mealybugs (white fluff hiding among the tubercles and axillary wool, where they are easily missed) and red spider mites are the usual offenders. See Pests and diseases.
See also
- Mammillaria — the genus overview
- Soil and potting mix · Watering · Repotting · Propagation — seed · Propagation — offsets · Pests and diseases