Discocactus is a genus of cacti highly prized by collectors worldwide. Precisely what makes them so attractive is uncertain. Some factors are likely their relatively compact size, unique and showy white flowers, and slow growth.
Species in this genus range from flattened to globose, with stems that rarely exceed 3 inches (7.5 cm) in height and are less than 10 inches (25 cm) in diameter. Stems are ribbed, sometimes tuberculate, with fuzzy areoles or dense spines. Most plants remain solitary but may form clumps. Flowering plants form a woolly terminal cephalium, from which flowers appear at the end of a long, thin floral tube. The nocturnal flowers are fragrant, and many growers tout them as the best-smelling of all cactus flowers. Discocactus bloom in summer, on and off. Flowers are generally white and open in the late afternoon and remain open until the following morning.
Growing Conditions
Light: These cacti will take full sun but prefer a little afternoon shade.
Water: Water with extreme care after the soil has dried out.
Temperature: During the rest period, keep Discocactus above 59°F (15°C) if grown on its own roots and at 46°F (8°C) if grafted.
Soil: The potting medium should drain well; use a 50% compost to 50% gravel, perlite, or pumice mix.
Grower's Tips
Discocactus are among the most difficult cacti to keep growing on their own roots and are almost always seen as grafted plants. If you attempt to grow them on their own roots, the soil must be highly free-draining, and water only after the soil has dried out, on sunny, warm days.
These cacti are tropical plants and should be kept warm in winter. Grafted plants are less cold-sensitive, but none have frost tolerance. Mature Discocactus stop growing and instead divert their energy into developing a cephalium. The cephalium is a specialized flowering head generally covered with fibers.
Links
- Back to genus Discocactus
- Succupedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus