Uebelmannia gummifera
| Light | Bright light with some protection from harsh midday sun |
|---|---|
| Water | Sparingly; allow to dry fully between waterings, keep dry in winter |
| Soil | Very free-draining, acidic mineral mix (see Soil and potting mix) |
| Temperature | Warm-growing; keep above about 10 °C, no frost |
| Propagation | Seed (primary); often grafted to speed growth |
| Toxicity | Not known to be toxic to cats or dogs |
Uebelmannia gummifera is a rare, slow-growing cactus from eastern Brazil, forming a globular to shortly columnar body clad in reddish-brown skin and topped with small yellow flowers. Like the rest of the Uebelmannia genus it is prized by collectors for its unusual colouring and fussy reputation, and it is one of the more challenging Brazilian cacti to grow well.
Description
Uebelmannia gummifera begins life as a solitary globe and slowly elongates into a short column, typically reaching a modest size over many years. The body is divided into numerous low ribs lined with closely spaced areoles, and it is the skin that draws the eye: a reddish-brown to purplish, waxy epidermis often overlaid with a fine scurf, quite unlike the plain green of most cacti. Short, dark spines sit along the ribs.
Small yellow flowers open in a ring near the crown, followed by inconspicuous fruit. As with other members of the genus, the exact colour and form vary between plants and with growing conditions, and stressed or brightly lit specimens tend to show the richest skin tones.
Distribution and habitat
The species is endemic to eastern Brazil, where it grows in the rocky uplands of Minas Gerais. Plants root in shallow, gritty, acidic substrates among quartz gravel and outcrops, often in exposed positions with sharp drainage and seasonal rainfall. This narrow, specialised habitat is part of what makes the whole genus uncommon in the wild and sensitive to collection and land-use pressure.
Cultivation
Uebelmannia gummifera has a reputation for being demanding, and it rewards patience more than fussing. Grow it warm — it dislikes cold, damp conditions — in an extremely free-draining, largely mineral mix that leans acidic rather than limey, since the genus is naturally adapted to acidic soils. Give it bright light to bring out the skin colour, with just a little shielding from the fiercest midday sun to avoid scorch on cultivated plants.
Water carefully during the warm growing season, always letting the soil dry fully before watering again, and keep the plant dry and warm through winter to prevent rot. Overwatering and cold are the two quickest ways to lose a plant. Because it is naturally slow, many growers raise seedlings grafted onto a vigorous rootstock to build size before growing them on their own roots. See Watering and Repotting for general technique.
Propagation
Seed is the standard and usually the only practical method, as the species is typically solitary and rarely offsets. The fine seed is sown on a warm, gritty surface and kept humid until germination; seedlings are slow and benefit from careful, steady conditions, which is a large part of why grafting is popular for getting young plants past their delicate early stages. See Propagation — seed and Grafting for full walkthroughs.
Common problems
- Rot — the most common cause of loss, almost always from overwatering, a poorly draining mix, or cold damp conditions; the body softens and discolours.
- Loss of colour — too little light leaves the skin dull and green rather than the desirable reddish-brown, and can cause etiolation.
- Pests — mealybugs (white fluff in the areoles and roots) and red spider mites (fine webbing, bronzed skin) are the usual offenders. See Pests and diseases.
Legal status
Like all members of the genus, Uebelmannia gummifera is listed on CITES Appendix I — the strictest level of protection — rather than the Appendix II listing that covers the cactus family as a whole. International trade in wild-collected specimens is therefore prohibited except under exceptional, tightly regulated circumstances. Plants that have been artificially propagated from seed can be grown and traded legally with the appropriate CITES documentation; collecting from habitat is not permitted. Growers should buy from reputable sources that can document their plants' cultivated, nursery-propagated origin.
See also
- Uebelmannia — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed · Pests and diseases