Parodia haselbergii
| Light | Bright light with some protection from the harshest afternoon sun |
|---|---|
| Water | Regularly in the growing season; keep dry and cool in winter |
| Soil | Fast-draining mineral mix with a little added humus (see Soil and potting mix) |
| Temperature | Keep above freezing; USDA zones 9b–11 |
| Propagation | Seed |
| Toxicity | Non-toxic to cats and dogs |
Parodia haselbergii is a small, globular South American cactus densely clothed in fine white spines and best known for its long-lasting orange-red flowers — a striking exception in a genus whose blooms are overwhelmingly yellow. Long grown under the name Notocactus haselbergii, it is a much-loved beginner's cactus, sometimes sold as the scarlet ball cactus. It belongs to the genus Parodia, which absorbed the old genus Notocactus.
Description
Parodia haselbergii forms a flattened to rounded globe, typically 8–15 cm across, that stays solitary for many years before slowly clustering with age. The body is divided into numerous low, spiralling ribs broken into small tubercles, each areole carrying a dense radiating cluster of thin, glassy white spines. This bristly white covering all but hides the green skin and gives the plant a soft, frosted look — though the spines are firmer than they appear.
The flowers are the plant's signature feature. Borne in a ring near the woolly crown, they are relatively small, cup-shaped and a warm orange to scarlet-red, quite unlike the buttery yellow typical of the genus. They open over a long period in late winter and spring and are notably persistent, lasting for weeks rather than days. Small dry fruits follow, holding fine seed.
Distribution and habitat
The species is native to southern Brazil, chiefly in the states of Rio Grande do Sul and Santa Catarina, where it grows on rocky outcrops and cliff faces in grassland country. In habitat it often perches in shallow pockets of gritty, humus-flecked soil among rocks, receiving strong light but also regular moisture from rain and mist during the growing season — conditions rather different from the arid deserts many people associate with cacti.
Cultivation
Parodia haselbergii is an accommodating and rewarding plant for the beginner, asking only for the basics done well. Grow it in a free-draining but not purely mineral mix — a little humus suits the Notocactus group — in bright light, with some shade from the fiercest summer sun to prevent scorching of the pale spines.
Unlike many desert cacti, it appreciates fairly generous watering through the warm months: water thoroughly, let the top of the mix dry, then water again. Reduce watering sharply in autumn and keep the plant cool and dry over winter, which both prevents rot and encourages the following season's flush of flowers. Feed lightly during active growth and repot every few years as the plant fills its pot.
Propagation
Seed is the usual and most reliable method. Sown on a warm, gritty surface kept humid, the fine seed germinates readily, and seedlings grow at a moderate pace. Older plants that have formed clusters can also be divided, and individual offsets removed and rooted, though the species is not a prolific offsetter. See Propagation — seed and Propagation — offsets for technique.
Common problems
- Rot — the main risk, almost always from cold, wet compost in winter or a mix that drains too slowly; the body softens and discolours from the base.
- Scorch — sudden exposure to intense sun can mark or brown the white spines and the skin beneath.
- Pests — mealybugs (white fluff among the spines and roots) and red spider mites (fine webbing, a bronzed cast to the skin) are the usual offenders. See Pests and diseases.
See also
- Parodia — the genus overview
- Soil and potting mix · Watering · Repotting
- Propagation — seed · Propagation — offsets