Scientific Name
Mammillaria spinosissima Lem.
Common Name(s)
Red-headed Irishman, Irish Red-head
Synonym(s)
Mammillaria spinosissima subsp. spinosissima, Mammillaria auricoma, Mammillaria pitcayensis, Mammillaria pilcayensis, Mammillaria centraliplumosa, Mammillaria haasii, Mammillaria gasterantha, Mammillaria crassior, Mammillaria virginis
Scientific Classification
Family: Cactaceae
Subfamily: Cactoideae
Tribe: Cacteae
Subtribe: Cactinae
Genus: Mammillaria
Origin
This species is endemic to Mexico.
Description
Mammillaria spinosissima is a cactus with dark blue-green cylindrical stems with short tubercles and almost hidden under a dense covering of spines. The stems grow up to 12 inches (30 cm) tall and up to 4 inches (10 cm) in diameter, solitary at first, later often producing offsets. Each areole bears 4 to 15 central and 20 to 26 radial spines. The central spines are bristle-like, up to 0.8 inches (2 cm) long, stouter than the radial spines, and vary in color from reddish and pinkish-brown to yellowish. Radial spines are straight, about 0.4 inches (1 cm) long, and vary in color from white and yellow to deep reddish-brown. Flowers are freely produced in spring and form a ring around the upper part of the plant. They are purplish or deep-pink, up to 0.8 inches (2 cm) long and up to 0.6 inches (1.5 cm) in diameter. Fruits are club-shaped, up to 0.8 inches (2 cm) long, greenish to dull purple, and contain reddish-brown seeds.
Hardiness
USDA hardiness zones 9a to 11b: from 20 °F (−6.7 °C) to 50 °F (+10 °C).
How to Grow and Care
To encourage better flowering, allow the plants to enjoy a cooling period in the winter and suspend watering. Unlike many other cacti, which use their ribs as storage devices, Mammillaria feature raised tubercles, from which spines emerge. When you water, the tubercles expand to allow for increased water storage. The flowers appear from these tubercles' axils on the previous year's growth, which accounts for their interesting halo effect. The cactus mustn't be exposed to prolonged dampness and sitting water. Never let your cactus sit in a dish of water. Lastly, ensure to fertilize during the growing season for the best results.
Repot as needed, preferably during the warm season. To repot Mammillaria, ensure the soil is dry before repotting, then gently remove the pot. Knock away the old soil from the roots, removing any rotted or dead roots. Treat any cuts with a fungicide. Place the plant in its new pot and backfill with potting soil, spreading the roots as you repot. Leave the plant dry for a week or so, then begin to water lightly to reduce the risk of root rot.
See more at How to Grow and Care for Mammillaria.
Cultivars
Links
- Back to genus Mammillaria
- Succupedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus
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