Ferocactus
Ferocactus is a genus of large, barrel-shaped cacti native to the arid southwestern United States and Mexico. The name comes from the Latin ferus, "fierce" or "wild," a nod to the genus's heavy, boldly coloured and often viciously hooked central spines — the very feature that makes these plants such prized subjects among collectors. Together with a handful of related genera they are the plants most people picture when they hear the common name barrel cactus.
Description
Most Ferocactus are solitary and, given time, grow into stout ribbed columns or globes — from modest football-sized plants to giants well over a metre tall and several hundred kilograms in the largest species. The body is divided into prominent, deep ribs lined with large areoles, and it is from these areoles that the genus makes its reputation: thick, rigid spines that may be straight or strongly hooked, and coloured in vivid reds, ambers, whites and greys that intensify when wet. Many species carry a cluster of flattened, broad central spines above a ring of finer radials.
Flowers appear in a ring near the crown, usually in summer, in shades of yellow, orange, red and purple, and are followed by fleshy, often yellow fruits. Compared with the spectacular spination, the blooms are relatively modest, though a well-grown mature plant in flower is a fine sight. Extrafloral nectaries at the areoles frequently attract ants, a natural feature that sometimes puzzles new growers.
Distribution and habitat
The genus is centred on the deserts of Mexico, with several species reaching into Arizona, California, Nevada, New Mexico and Texas. Plants grow on rocky slopes, gravelly flats and desert washes, typically in fast-draining mineral soils under full sun. Some of the larger species famously lean towards the south or southwest as they age — the origin of the folk name "compass barrel."
Like all members of the Cactaceae, Ferocactus species are listed under CITES Appendix II, and wild collection is restricted; nursery-grown plants are widely and legally available.
Notable species
- Ferocactus wislizeni — the fishhook barrel, with stout hooked central spines and orange to yellow flowers; a classic of the Sonoran Desert.
- Ferocactus latispinus — the devil's tongue barrel, noted for its broad, flattened, hooked central spines.
- Ferocactus emoryi — a robust species with a single heavy hooked central spine and red to orange flowers.
- Ferocactus glaucescens — a blue-green, symmetrical species with amber spines and clear yellow flowers; a beginner favourite.
- Ferocactus pilosus — the Mexican fire barrel, prized for dense, brilliant red spines.
- Ferocactus cylindraceus — the California barrel, a large species of the southwestern deserts.
- Ferocactus histrix — a broad, many-ribbed species whose immature flower buds are gathered as the traditional food cabuches.
Cultivation
Barrel cacti are among the more forgiving large cacti to grow, asking mainly for strong light and sharp drainage. Plant them in a gritty, mostly mineral mix and give the brightest position available — full sun brings out the best spine colour, while too little light produces weak growth and dull spines. Water generously during the warm growing season once the mix has dried, then keep plants dry and cool through winter; standing wet, especially in cold weather, is the usual cause of rot.
Most species tolerate considerable heat and, when bone dry, brief light frost, though tender species and young plants should be protected from freezing. They are slow but steady, and a large specimen represents many years of growth, so repot young plants as they fill their containers and handle the spines with care — see Repotting and Watering for general technique.
Propagation
The genus is raised almost entirely from seed, as most species remain solitary and rarely offset. Seed germinates readily on a warm, humid mineral surface, though seedlings grow slowly and take years to develop their characteristic spination. The occasional clustering plant can be divided, and choice or slow forms are sometimes grafted to speed them along, but seed remains the standard and most rewarding route.
Hobby and cultivar notes
Ferocactus is grown chiefly as a "species" collection — the appeal lies in the natural spine colour and form rather than in named cultivars, of which there are relatively few compared with genera like Astrophytum. Growers prize well-spined, symmetrical plants and forms with particularly red or golden spines. Because mature plants are large and heavy, many hobbyists enjoy the long-term challenge of growing a barrel from seed to a substantial specimen. The genus sits alongside Echinocactus (the golden barrel and its relatives) in the broad "barrel cactus" grouping, and the two are often confused.
Common problems
- Rot — from overwatering or a poorly draining mix, particularly in cold or dark conditions; the base softens and discolours.
- Weak spination and etiolation — insufficient light produces pale, narrow, poorly coloured growth.
- Pests — mealybugs (including root mealybugs) and red spider mites are the usual offenders; see Pests and diseases.
- Corky scarring — cosmetic patches of brown, cork-like tissue that are common on mature barrels and generally harmless.
See also
- Echinocactus — the related "barrel" genus (golden barrel and kin)
- Astrophytum · Grafting · Soil and potting mix · Watering · Propagation — seed · Repotting · Pests and diseases