– Ferocactus (2002)

By Don Krechel (January 2002)

The genus Ferocactus will be very familiar to most cactus enthusiasts, for it is one of the most common cacti found for sale – usually at a very young age. Feros are normally grown for their good show of strong, striking and colorful spine formations. As with many of the larger cacti, even under optimum conditions, feros won’t be expected to flower until 12-25 years old.

They should be given full sun for best spine development and color. Pot-grown plants are smaller and grow slower due to the confinement of their shallow, extensive and rambling root systems. But they are just as spiny and colorful.

The many deep, angled ribs on specimens with a mature diameter help shade the body and prevent scorching. Feros are known to scorch under glass if kept in strong, full sun. It has been found that stronger spination and more flowers are produced if the plants are grown under rigid plastic rather than glass.

Feros require a coarse substrate of 50 percent drainage, 25 percent peat and 25 percent roughly sieved mature compost. Mineral salts (trace elements found in cactus fertilizer) are essential. The salts also heighten the spine color. In their growth period, these cacti should only be watered moderately. They need a dry and very cool winter rest.

Many species are hardy to 20 degrees F and tolerate frost. My feros are left outside in the fall, even when the night temperatures drop to 25 degrees F. I believe this helps them enter the required dormant cycle. Some feros can withstand far lower temps.

I have a Ferocactus hamatacanthus planted in the ground outside that has survived our winters for the last seven years with no problem. Although it has the protection of a cold frame, it did get some cold damage this past winter. Last summer, I also planted three of the closely related F. setispinus. They all made it through this past winter, and as of June 2001 had flowered several times!