Looking past the thorns of cacti
Did you know that all but four species of cacti are native to the Americas? Most have fleshy or succulent stems. All of those that grow naturally in the U.S. are stem succulents with a very woody tissue except for tall species and chollas.
Cacti, like every group of living organisms, show a certain amount of variation from individual to individual. For that reason, you should not expect every plant of a given species to look exactly alike, e.g. spines may vary somewhat in length or color
There are six species of cacti common to the Southwest:
Opuntia - Prickly Pears and Chollas: Unlike most other cacti, chollas and prickly pear are many-branched, each branch arising from another as in a tree. Most species fall into one of two types: those having flat, broad joints (pads) or those having cylindrical joints.
The name Prickly Pear is applied to all cacti with flat-jointed stems called pads. The fruits or tunas are edible and are used for making jams, jellies, a refreshing cactus juice, wine and vinegar.
The pads of many varieties are an important source of food and medicine to man and animals. The Cholla group varies in size from 12 inches to 15 feet tall. Many of the Chollas will become reddish or purplish in times of drought or cold weather. These cacti have spines to be reckoned with, so may I suggest containers for them; however, the Cactus Wren likes to make her nest in them.
Cereus: This group of cacti is more likely to be native to South America than North America. Many cerei are tree-like and extremely massive, while others are bushy or even vine-like. The stately Saguaro, monarch of the desert, is one of the largest cacti anywhere, rising up to 50 feet. Many of this species are night bloomers, and all need to be protected from hard frost.
Echinocereus - Hedgehog Cacti: The Hedgehog cacti include nearly 50 different varieties, varying in sizes, shapes and flower color.Their usually showy flowers make these plants especially attractive. The Fendler's Hedgehog and the Engelmann's Hedgehog are the most common in our area.
Ferocactus & Echinocactus - Barrels: Fishhook and Barrel Cactus are called fishhook due to the shape of the central spine. All members of this family have prominent ribs, and are all densely armed with heavy spines. The Compass barrel (Ferocactus cylindraceus) grows slowly to 8 feet and 32 inches wide. They display orange or yellow flowers like a crown in late spring.
The Fishhook barrel cactus (Ferocactus wislizenii) only reaches 6 feet and is 32 inches wide. Yellow or dark orange blossoms appear on the crown in late spring and summer.
Coryphantha & Escobaria - Pincushions: Coryphantha are in general bigger rounded plants with large tubercles and stouter spines.Escobaria are more egg-shaped, with a large number of small thin spines. The spines, most often translucent white, completely hide the surface of the plant.
This group is composed of plants that have tubercles only. These are grooved on the upper surface, this grooving runs from the base of the tubercle to the spine-bearing areole. It is at the very top of the plant and always at the very end of the groove farthest from the spine that flowers originate.
Mammillaria - Pincushions & Fishhooks: Mammillaria can be grouped into species that have only straight spines (pincushions), and those whose central spines are hooked at their tips (fishhook). Occasionally, individuals of most species of fishhooks do not develop hooks on their spines. They do not have grooved tubercles, nor do the flowers form at the very top of the plant; rather they orginate at the base of the tubercles which were produced the previous year.
Sandy or rocky soil with good drainage. Heavy clay soil should be amended with sand and decomposed granite because cacti must have good drainage; they do not like their roots wet for any length of time. Some cacti are frost-sensitive, so check the variety.
When handling cactus, wear heavy gloves, an old towel or a piece of old carpet to avoid injuring yourself or your plant.A scared cactus will survive, but the scare will always be visible, so handle them gently. Tip: if you get several small spines in your fingers, they are easily removed by a piece of duct tape.
"Heavy and infrequent" or "less is best" are good rules to follow.Once every two weeks should be sufficient. Try to simulate our heavy, infrequent summer rains. Do not water from November thru February.
Withholding water encourages dormancy and will lessen the chances for root rot or excessive freeze damage in bitter cold.
Remember, cacti naturally shrivel during drought periods (and in winter). Many require no supplemental watering once they are established.
Rots comprise the bulk of cacti diseases. They usually occur when the cacti has been injured or over-watered. If injured, dust the wound with sulfur, otherwise water correctly and they are relatively disease free.
For more information, contact The University of Arizona Mohave County Cooperative Extension, 101 E. Beale Street, Kingman, AZ 86401-5808 or call (928) 753-3788.