Mammillaria WINTERAE

Mammillaria WINTERAE - Winter's mammillaria, Mammillaria winterae.

Mammillaria is a large genus of low-growing succulent plants in the cactus family (Cactaceae), comprising about 170-200 species distributed mainly in Mexico, as well as in the southern United States, Central America, the Caribbean region, and the northern part of South America. In nature, members of the genus occur in deserts, semi-deserts, dry shrublands, tropical deciduous forests, on limestone slopes, rocky plains, and in mountainous areas with bright sun and well-drained soils.

The plants usually develop as solitary or clumping globose, flattened-globose, cylindrical, or short-columnar cacti. Instead of ribs, they have separate tubercles, or mammillae, on the tops of which are areoles with radial and central spines. In many species, wool, bristles, buds, flowers, and fruits form in the axils between tubercles.

Flowers typically form in a ring closer to the apex of the stem, and can be white, cream, yellow, pink, red, or purple. After pollination, elongated or club-shaped fruits develop, often red or pink, containing small brown or black seeds with a pitted or reticulate surface.

Mammillaria winterae has a solitary, globose stem reaching 30 cm (12 in) in diameter. Axils (the depression between tubercles (mammillae)) are heavily woolly. Radial spines are absent. Four central spines are brownish, up to 3 cm (1.2 in) long. The flowers are pale yellow, 3 cm (1.2 in) long, 2.5 cm (1.0 in) in diameter.

Mammillaria seeds are small, dark brown or black, rounded or slightly oval. Seed germination under careful greenhouse conditions is usually about 50-80%.

Sowing is carried out in spring or year-round in the presence of stable grow lights. A sterile fine-grained mineral substrate based on sifted cactus soil, fine sand, perlite, and mineral grit is used. Seeds are distributed over the surface, lightly pressed into the moist soil, and covered with a minimal layer of fine sand or not covered at all. The sowing is moistened with a spray bottle with a weak solution of potassium permanganate or biofungicide with the addition of a growth stimulant: SUPERthrive, HB-101, Aminozol, Epin, or Zircon. The container is covered with a transparent lid or placed in a mini-greenhouse.

Germination is carried out under bright indirect light and a temperature of about 22-26 °C (72-79 °F), without direct overheating under the sun. The surface is maintained moderately moist, but not wet; moistening is performed only by fine spraying. Sowings are ventilated daily, and condensation is removed, since moisture stagnation is dangerous for mammillaria seedlings and quickly causes fungal damage.

The first sprouts may appear in 7-10 days; the usual germination period is 10-21 days; the maximum possible period under temperature fluctuations or partial drying of the surface can stretch up to 4-6 weeks. After seedlings appear, the cover is gradually opened; seedlings are kept under bright indirect light and cautious moistening. Pricking out is carried out after noticeable strengthening of the plants and appearance of the first spines, usually no earlier than after several months, with minimal damage to the roots.

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For cultivation, the brightest possible location with several hours of direct sun per day is selected. South-, southeast-, and southwest-facing windows are best suited, while supplementary lighting is recommended during the overcast season. After a dark overwintering or repotting, the plant is gradually acclimated to direct sun to prevent burns on the stem.

During the period of active growth, a temperature of about 20-28 °C (68-82 °F) is maintained with good air circulation. The plant is heat-loving and does not tolerate cold dampness. Overwintering is carried out bright, dry, and moderately cool, around 8-12 °C (46-54 °F), with nearly complete cessation of watering. At lower temperatures, moist substrate is particularly dangerous and can cause root rot.

Watering is carried out moderately, only after the substrate has dried out completely. In spring and summer, the soil is moistened in small portions, with mandatory draining of water from the tray. In autumn, watering is gradually reduced; in winter, the plant is kept almost completely dry. Water ingress into the axils between tubercles is undesirable, especially under cool conditions and weak ventilation.

A loose mineral substrate for cacti is used, with additions of coarse sand, fine stone chips, pumice, zeolite, perlite, or other inert aerators. The organic portion is added moderately. High drainage is placed at the bottom of the pot, and a shallow, stable, and not overly spacious container is selected.

Fertilizer is applied only during the period of active growth, once every 4-6 weeks with a weak solution of fertilizer for cacti and succulents with reduced nitrogen content. Excess nutrition causes loose growth and reduces resistance to rot. Repotting is carried out in spring as the pot becomes filled with roots; after repotting, the plant is kept for several days without watering. Pruning is not required, and separating lateral offsets is possible only on well-expanded specimens.