Mammillaria heyderi - Cactus

Mammillaria heyderi is a botanical cactus recognisable by its low, regular silhouette, slightly depressed at the apex, and appreciated for its pastel crown flowering. This species is very well suited to cultivation in a very bright interior, a conservatory or a temperate greenhouse. It is a collector's cactus, sought after for the diversity of its forms. Its cultivation is not difficult as long as it is given sufficient light and a winter rest period.

Belonging to the Cactaceae family, Mammillaria heyderi is a species widely distributed between the south-western United States and northern Mexico, in desert environments or dry scrub. It is found on stony, sandy, alluvial soils. It is a rather variable group, composed of several subspecies or forms recognised by botanists.
The plant most often remains solitary. Its stem has a globose to flattened shape, sometimes resembling a wide disc with age. In cultivation, it reaches 5 to 12 cm in height and 8 to 15 cm in diameter, sometimes more in older specimens. Its epidermis bears small protuberances. These short, conical tubercles bear dense, fine, white to greyish radial spines complemented by 1 to 4 more robust central spines, which are straight or slightly curved and whitish to brownish. The whole gives a well-armed plant. The funnel-shaped flowers measure 2 to 3 cm in diameter. They open near the apex and are arranged in a regular crown; their colour varies from yellowish cream to pale pink, with a darker central vein. In the wild, this species produces elongated, red to coral red fruits containing small dark brown seeds.

Indoors, this Mammillaria requires very bright light with direct sun, a dry environment, around 30 to 50% humidity, and temperatures of 18 to 30°C during the growing season, with a dry winter rest at around 8 to 12°C. It needs some care, the main difficulty arising mainly from lack of light and excess water in winter. Place it near a south- or south-west-facing window, in a bright conservatory or a well-ventilated greenhouse.

Mammillaria will benefit from a stay outdoors from spring to autumn, exposed to the sun and sheltered from excessive rain. Bring it in before the first frosts to overwinter in a bright, dry, cool place, protected from frost.

This collector's plant pairs well with other small succulents such as Haworthia fasciata ‘Concolor’, Crassula ‘Buddha’s Temple’, whose geometric columns introduce a very different relief, Kalanchoe ‘Oricula’, more spreading, with thick leaves, and Gasteria ‘Little Warty’, with rough, spotty foliage. These plants display very varied textures, but they have similar cultivation requirements, allowing them to be grouped near a window or in the conservatory.