Scientific Name
Mammillaria hahniana Werderm.
Common Names
Old Lady Cactus
Synonyms
Mammillaria hahniana subsp. hahniana
Scientific Classification
Family: Cactaceae
Subfamily: Cactoideae
Tribe: Cacteae
Subtribe: Cactinae
Genus: Mammillaria
Description
Mammillaria hahniana is a cactus with solitary or clustered stems covered with dense white bristles and fine spines. It grows up to 10 inches (25 cm) tall and up to 20 inches (50 cm) wide. Stems are up to 5 inches (12.5 cm) in diameter, at first spherical than cylindrical. Flowers are reddish-purple, up to 0.6 inches (1.5 cm) in diameter, appear in spring and summer, sometimes forming a complete ring around the stem's apex.

Photo via ortosemplice.it
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, the Mammillaria feature raised tubercles, from which spines emerge. When you water, the tubercles will 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, make sure to fertilizer during the growing season for the best results.
Repot as needed, preferably during the warm season. To repot a cactus, make sure the soil is dry before repotting, then gently remove the pot. Knock away the old soil from the roots, making sure to remove any rotted or dead roots in the process. See more at How to Grow and Care for Mammillaria.
Origin
Native to central Mexico.
Links
- Back to genus Mammillaria
- Succulentopedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus
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