– Mammillaria geminispina (2008)

By Ruby Smith (March 2008)

There are about 150 more or less species of mammillarias. Mammillarias can be found in the United States as well as central Mexico, Central America and even northern South America. In their range, you can find mammillarias from sea level to high elevations. They also vary in size from tiny individual plants about 1 inch in diameter to clumping types and columnar types about 1 foot tall.

The name “mammillaria” comes from the Latin word for nipple, referring to the tubercles that mammillarias have instead of ribs like most cacti. Mammillarias can be difficult to grow or quite easy, even from seed. This species comes from areas of steep limestone, marlstone and/or slate rocks.

Mammillaria geminispina mounds as it ages. Large clumps are very attractive, with many heads covered with white spines. In cultivation, the flowers are very small, beautiful, carmine red flowers. They form a ring around the top of the plant on tissue from the previous year.

M. geminispina is sensitive to being overly wet. Potting soil should be porous. Water on warm days when soil is dry. Average minimum temperature is 50 degrees F.

There are two recognized subspecies of M. geminispina. One has two central spines that are white with dark tips, and the other has white central spines.

Seed-grown plants can take four to eight years to bloom. If you are looking for a plant group with great bodies, beautiful spine shapes and colors and diverse flowers, then mammillarias are your plants.