GV Gardeners: Intense barrel cactus flowers enhance desert

Shown is an example of flower development on this perfectly round Barrel Cactus: several of last year's now-shaggy blossoms; a half-dozen newly opened bright orange flowers; and many still-tight buds waiting to share their vivid color.

Look across the desert floor and be amazed by the large number of plump barrel cactus with brightly colored summer blossoms that are scattered throughout. Usually just blending in, now each barrel stands out with its crown of brilliant orange, red or yellow flowers.

Commonly called barrel cactus, the genus Ferocactus is from the Latin word “ferox” meaning fierce, and the Greek word “kaktos” meaning thistle … very appropriate. Furthermore, despite folklore, barrels are not filled with fresh water to cure thirst in a parched desert. Their internal moisture is very alkaline and can worsen effects of dehydration.

Shaped like a barrel, this genus has stout spines with hooked or sometimes straight ends. These spines may be gray, brown, white, yellow or brilliant red. With high temperatures, produced around the top of each are funnel-shaped blossoms ranging from yellow to red depending on the variety.

Resulting fruits resemble small pineapples, elongated and vivid yellow often decorated by dried flower remnants. Picture colorful flowers forming a circle around the top of the barrel surrounded by a ring of the previous year’s yellow fruits. The fruits may remain on the plant for a year or more unless eaten by birds or other wildlife. If the spent fruit is left attached, buds will still form for the following season’s flowers, so it is not necessary to remove them.

Growing to 3 feet or taller, Fire Barrels (Ferocactus gracilis) are popular because of their many bright red spines which retain their color throughout the life of the plant. Other commercially available red-spine barrels include F. pringlei and F. stainesii. All are especially breathtaking when backlit by the sun or moistened by light rainfall.

Quite common in the open desert and frequently known as Arizona Barrel or Fishhook Barrel, Ferocactus wislizeni is the largest barrel cactus found in the United States. It may mature at 8 feet tall and has lived to 100 years. As it grows, this barrel becomes cylindrical in shape and leans toward the southwest direction, so it is also referred to as Compass Barrel.

In general, desert cactus can endure long periods of drought by storing within their tissue as much water as is available. Water is taken up quickly and efficiently through their roots; however, they do not have a way to rapidly get rid of any excess. They may then swell until splitting open or developing rot. The key to water management of most cactus is to underwater rather than overwater.

Barrel cactus are key elements in the xeric landscape, whether it be the endless desert floor or in the confines of our backyards. With their dazzling flowers, soft-yellow fruits, and multi-hued spines, these chunky succulents add further “old west” character to the environment.

Mary Kidnocker is a University of Arizona Master Gardener who lives in the Green Valley area. Her articles are featured weekly.

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