Light
Bright Indirect Light
Requires bright filtered sunlight or partial shade; avoid harsh noon sun.
Reference image Mammillaria evermanniana
Evermann's Nipple Cactus
Overview
Mammillaria evermanniana is a slow-growing, globose to short-cylindrical succulent cactus in the family Cactaceae. Highly prized among succulent collectors, it is known for its compact growth habit and beautifully dense woolly axils 1.
Taxonomy and Naming
This species was named in honor of the American ichthyologist Barton Warren Evermann. Belonging to the massive genus Mammillaria, it is characterized by its distinct tuberous tubercles (nipples) that arranged in spiral patterns.
Distribution and Habitat
This species is endemic to Mexico, specifically occurring on the islands in the Gulf of California, such as Isla Cerralvo, and parts of the Baja California Sur peninsula 2. It thrives in arid desert conditions, hugging rocky outcrops and volcanic soils.
Appearance
The globose stem can grow solitary or occasionally clump from the base. It features close-set tubercles with dense white wool in the axils, especially near the apex. The spines are relatively short and less menacing than other species. Small, bell-shaped flowers of pale yellow or cream-pink emerge in a ring near the crown 1.
Culture and Management
Cultivating Mammillaria evermanniana is highly rewarding due to its low maintenance needs. It requires porous soil and sparse watering. Keeping the substrate bone-dry during the winter resting phase is critical to prevent rot and encourage spring blooms.
Common Cultivation Mistakes
Overwatering and poor soil aeration are the primary causes of failure, rapidly leading to root rot. Insufficient light leads to etiolation, causing the spherical stem to stretch and weaken, losing its characteristic compact shape.
Bibliography
References
Watering
10-30 Days
Allow soil to dry out 100% between waterings. Suspend watering in winter.
Soil
Fast-draining, mineral-rich cactus mix
Thrives best in mineral-heavy cactus soil mixed with plenty of pumice.
Safety
Pet Friendly
Non-toxic, safe for pets and children. Spines are small and minimal.
Difficulty
Easy
Very easy to care for, ideal for beginners who tend to forget watering.
Native Habitat
Mexico (Baja California Sur)
Native to the dry, stony landscapes of Baja California Sur in Mexico and its surrounding islands in the Gulf of California. It grows in coastal desert scrub and volcanic slopes under intense heat and dry winds.
Frequently Asked Questions
Is Mammillaria evermanniana toxic to pets?
No, this cactus species is completely **non-toxic** to cats and dogs. However, it is best kept out of reach to prevent pets from getting poked by the small spines.
How often should it be watered in a pot?
During summer, water roughly every 10 days once the soil is completely dry. In winter, the plant enters dormancy, and watering should be stopped almost entirely (once every 30-40 days or not at all).
What kind of soil should be used?
Use a specialized cactus and succulent soil mix with high amounts of pumice, perlite, and coarse sand for excellent drainage. Standard potting soil is too heavy and will cause rot.
How much sunlight does it need?
It thrives in bright, filtered sunlight or partial shade, receiving at least 4-6 hours of light daily. Avoid harsh direct midday sun, which can scorch the epidermis.
How can I encourage it to bloom?
To promote blooming, allow the cactus to undergo a dry, cool winter dormancy (around 5-10°C) with no water. Flower buds will form as temperatures rise in spring.
What is its growth rate?
Mammillaria evermanniana is a very slow-growing cactus. It maintains its neat, compact shape for years without needing frequent repotting.
When should it be repotted?
Repot only when the plant outgrows its container, typically every 2-3 years in early spring. Always choose a pot that is only one size larger than the previous one.
Is it frost hardy?
It can tolerate brief cool temperatures down to 5°C if kept dry, but it is not frost-hardy. Move it indoors during winter to protect it from freezing temperatures.
Are the white woolly structures on the cactus normal?
Yes, the white woolly tufts between the tubercles and on the crown are natural features of this species. It is not a disease or pest, but a natural protection mechanism.
What is the most common cause of death?
Overwatering is the leading cause of death. Roots left in soggy soil rot quickly, and this rot spreads upward, softening and destroying the cactus. Always let the soil dry out entirely.