Mammillaria melaleuca aka Mammillaria Melaleuca

Mammillaria melaleuca is a small cactus from Mexico. It belongs to the cactus family, Cactaceae. Kew places its native range in Tamaulipas. LLIFLE also lists central Mexico. It grows in desert or dry shrubland. Wild sites lie at 4,265–6,562 feet [1,300–2,000 metres] above sea level. Wild plants may stay single for many years. In pots, they form clumps more readily.

The round, bright green stems reach about 0.33 feet [0.10 metres] tall. Growth is slow, but offsets build neat mounds over time. A clump can fill a pot 0.82 feet [0.25 metres] wide. The thick taproot joins the stem in a swollen rootstock. Firm, rounded tubercles project from the stem. These reach up to 0.16 feet [0.05 metres] long. Young areoles bear white hairs, which disappear with age. Each areole has six to twelve spreading radial spines. These range from white to pale yellow. One darker central spine is usual, though three may occur. Its tip is almost black.

Spring brings sweet-scented, lemon-yellow flowers with a funnel shape. Their length and width reach 0.10–0.13 feet [0.03–0.04 metres]. Some reach 0.20 feet [0.06 metres]. The tepals join at their bases and have red tips. Their backs show pink-red stripes. The oblong fruits range from green to greenish brown. Some also show red patches. The seeds are dark brown, close to black.

This cactus suits pot collections with strong light and good airflow. LLIFLE rates it as easy to grow. Use a very open cactus mix with little organic matter. Choose a small pot that still gives the taproot enough depth. Drainage holes are essential, as wet roots rot with ease. Repot every two to three years. Water during summer, but avoid leaving the mix damp. Excess water and shade can cause swollen, untidy growth. Keep the plant dry through winter and avoid humid resting conditions.

Frost can harm this species, though dry plants cope better. LLIFLE reports brief survival at -5°C, not reliable frost hardiness. A winter minimum of 5–8°C offers safer growing conditions. During growth, use feed low in nitrogen. The source recommends more potassium and phosphorus. Grow new plants from seed or detached offsets. Seedlings need ventilation and protection from full sun. Allow offsets to reach one-third of the parent's size before removal.