– Mammillaria spinosissima (2012)

By Jeanne Yochim (April 2012)

The stem, initially solitary and later clustering, of Mammillaria spinosissima has a markedly cylindrical shape. The plants, when 1 foot tall, have a stem diameter of about 4 inches. The species is found on rocky outcrops of hills, invariably on limestone rock. Its habitat is reported to be in central Mexico.

The species epithet means “very spiny,” and obviously refers to the rather dense spines, which are usually yellow and protrude from the stem. The flowers develop near the crown, forming a garland. They are crimson red and roughly 5/8 inch across.

M. spinosissima is very undemanding, and nowadays it is grown in large quantities in commercial nurseries. The plants are fast-growing, elegant in appearance and relatively tolerant of growers’ mistakes.

They need as much light as possible without burning the plants to encourage the heaviest spine formation. Give the plants regular water in the summer, but keep them dry in the winter. M. spinosissima should be wintered at temperatures around 50 degrees to ensure that flowers will be produced in the next season.

Unopico is one of the few cultivars among Mammillaria species. It has not been around long, but is popular because of its unusual spines. It has been increased by micropropagation, and there are now thousands in commerce.

This cultivar is best increased vegetatively, the only way of maintaining the exact features and properties of the parent plant. Seeds are viable but result in considerable variation. Some seedlings will have the characteristics of this named form, but most revert to type.

My new cactus is a very nice addition to my small cacti collection, and I am happy to give it a new home.