Mammillaria

This group consists of about 250 species of cacti that are natives of Mexico, Columbia, Guatemala, Honduras, the southern US, Venezuela, and the West Indies. They range from small plants, �-inch in size to huge clusters over 3 feet across. They have cylindrical or globular shapes, which may clump or remain solitary. The tubercles are spirally arranged along the body and from these grow many spines. The spines come in a variety of colors, shapes and sizes and really add to the plant's beauty. In the spring or early summer, a profusion of beautiful, small flowers are produced in a ring around the crown. Their colors may be white, cream, or shades of reds, pinks, and yellows. Unlike most cacti whose flowers are borne on the areoles, the flowers of Mammillarias are produced from the joints of the tubercles. They are followed by red seedpods. Many of these plants are excellent beginner's plants because they grow quickly from seed and will flower when quite young. M. zeilmanniana (Rose Pincushion) is one of the most commonly grown Mammillarias. It has a purplish-black body, which quickly grows to form a mound of numerous heads. For several months in the spring, a profusion of dark pink flowers are produced when the plant is only about �-inch in diameter. This plant can reach a height of 6 inches with a spread of 2 feet. Care should be taken not to overwater this plant as it may rot. M. hahniana (Old Lady Cactus; Old Lady of Mexico; Birthday Cake Cactus) forms a solitary, light green plant at first, eventually clumping or branching at the tip. It can reach a height of up to 8 inches with a spread of 2 feet. The Birthday Cake Cactus is covered in short, white spines that may become long and curly like white hair. In the spring, a ring of dark pink flowers are produced at the ends of the stems. They are followed by a ring of small, erect, red pods that grow at the crown. They resemble candles on a cake, thus the common name. M. bocasana (Powder Puff Cactus; Snowball Cactus) forms a spherical, light or dark bluish-green body up to 2 inches in diameter. This solitary plant can eventually form clusters up to 10 inches wide. Its slender tubercles are �-inch long and arranged spirally along the body. They are covered in wispy, white, hair-like spines. A single (sometimes as many as three), red or straw-colored, central spine grows from the tubercle. Periodically from spring to fall, a profusion of small, pinkish-peach flowers are produced around the crown. These are followed by long, finger-like, red fruits. M. guelzowiana forms 11/2-inch wide stems that are covered thickly in white, hair-like spines. Rigid, tan, radial spines and a hooked central spine grow from this plant. If they are provided with enough summer heat, but not harsh sunlight, gorgeous flowers up to 2� inches across will be produced. They are bright pink with a light, spicy fragrance.

Pot Cultivation

These plants need a temperature of 41� F. Grow them in rich, porous, sandy soil and let the soil dry out between waterings. Repot in the spring when their roots become cramped. Generally, they should be repotted every other year in order to provide fresh soil. However, this doesn't necessarily mean they'll need larger containers. Fill about a quarter of the pot with broken crocks, gravel, etc. to promote good drainage. Firm the potting soil. After repotting, do not water for a week or more.

Propagation

These plants may be increased by sowing seeds or planting offsets. The seeds may be sown in containers filled with a general-purpose cactus and succulent mix. Sprinkle the seeds evenly over the surface of the compost. Cover the seeds lightly with some grit, moisten the container and place in an area with high humidity and warmth. Transplant the seedlings when they are large enough to handle. Waiting too long until they are overcrowded can cause rot. Gently separate them so as not to damage the delicate roots. Transplanting will be easier if the soil is slightly moist. Seedlings can be potted singly or with several to a pot. They seem to do better if a few are together than by themselves.