Parodia horstii
| Light | Bright light with some direct sun; a little shade from the harshest afternoon heat |
|---|---|
| Water | Regularly in the growing season once the soil dries; keep dry and cool in winter |
| Soil | Free-draining but slightly richer than most cacti tolerate — a gritty mineral mix with a little humus (see Soil and potting mix) |
| Temperature | Keep above freezing; a cool, dry winter rest suits it best (roughly USDA zones 9b–11) |
| Propagation | Seed (primary); occasional offsets |
| Toxicity | Non-toxic to cats and dogs |
Parodia horstii is a globular to shortly columnar cactus from the highlands of southern Brazil, prized among collectors for its reddish-brown spines and its unusually rich flower colour, which ranges from warm orange to coppery or purplish-red — a striking departure from the mostly yellow-flowered relatives of the group. Formerly placed in the genus Notocactus (as Notocactus horstii), it belongs to the group of South American cacti now folded into Parodia, and it is one of the more vividly flowered members of that assemblage.
Description
Parodia horstii forms a solitary, deep green stem that begins spherical and slowly lengthens into a short column with age, typically reaching around 10–20 cm tall. The body carries numerous low, closely set ribs lined with felted areoles. From each areole radiate slender spines with a reddish to reddish-brown cast — the finer radial spines paler, the central spines darker and more prominent — a colouring that gives established plants a distinctly warm-toned appearance.
The flowers open from the woolly crown of the plant, generally in the warmer months. They are the species' main attraction: cup- to funnel-shaped blooms in shades of orange to reddish, sometimes leaning toward a coppery or purplish-red, set off by dense wool and bristles in the flower zone. As with other Parodia, several buds may open in succession over a season.
Distribution and habitat
The species is native to the state of Rio Grande do Sul in southern Brazil, where it grows on rocky slopes and outcrops in grassland country. Plants root in shallow, gritty pockets among rock, exposed to strong light but benefiting from the seasonal rains and cooler nights of the region. This upland, summer-rainfall origin explains why the plant appreciates more regular watering in growth than many desert cacti, alongside sharp drainage.
Cultivation
Parodia horstii is a rewarding and fairly forgiving grower for a globular cactus. Give it bright light with some direct sun to bring out good spine colour and to encourage flowering, easing off only during the fiercest afternoon heat under glass. Unlike strict desert species it enjoys steady moisture through spring and summer: water thoroughly once the mix has dried, then let it approach dryness again before the next drink. A slightly more open, humus-containing mineral mix suits its highland origins better than a pure sand blend.
Through winter, keep the plant cool and dry to allow a proper rest — this both prevents rot and improves the following season's flowering. See Watering and Repotting for general technique.
Propagation
Seed is the usual and most reliable method, germinating readily on a warm, moist mineral surface in the manner typical of the genus; see Propagation — seed. Plants are generally solitary, but where offsets do form they can be removed and rooted as with other offsets. Named forms and choice spine colours are maintained largely through seed selection.
Common problems
- Rot — the commonest cause of loss, from cold, wet conditions or a slow-draining mix, especially over winter; the base or crown softens and discolours.
- Etiolation — too little light makes the stem pale and stretch upward, spoiling its compact form and dulling spine colour.
- Pests — red spider mites (fine webbing and a bronzed, dulled skin) and mealybugs (white fluff lodged in the wool and areoles) are the usual offenders; see Pests and diseases.
See also
- Parodia — the genus overview
- Soil and potting mix · Watering · Propagation — seed · Propagation — offsets · Repotting