Desert gardening
Cacti are drought-tolerant,
great for xeriscaping


July 30, 2009

by Lupe Cook,
Victoria County Master Gardener

edited by Charla Borchers Leon,
Victoria County Master Gardener
Editor's Note: This is Part II of a two-part series on desert gardening. Included in this article is information about the numerous varieties of cacti that were planted in the garden of Master Gardeners Lupe Cook and Roy Cook.

I was overwhelmed at the different cacti shapes and sizes, when doing my research for my own desert garden. To reiterate from last week's article, my son, David, and I researched 104 varieties and found there are small rounded, barrel, flat, or cylindrical shapes; there are shrubby, segmented and sprawling kinds; and there are large columnar and tree-like giants. The growing conditions vary from one plant to another. They are drought-tolerant and great for xeriscape gardening. Full sun and low moisture are major factors.

Here are a few that are now thriving in our garden.

COLUMNAR-TYPE CACTI

Blue Candle - Myrtillocactus geometrizans
Origin: Mexico to Guatemala.
Height: 4 feet tall.
Blooms: white/near white flowers in mid-spring.
Semi-hardy above 25 degrees.

Saguaro Cactus - Carnegiea gigantean
Origin: Mexico and Sonora Desert in Arizona.
Height: 15 to 50 feet. Its growth rate is 1 inch per 10 years. The slow growth and capacity to store water allows it to bloom creamy-white, 3-inch wide flowers with yellow centers in May to June. Saguaro can only be pollinated by cross-pollination from a different cactus. The flower and nectar attract birds, bats and insects; pollinated when these are acquiring the nectar. It is the Arizona state flower.

Organ Pipe - Stenocereus thurbei
Origin: Sonora Desert from southwestern Arizona to western Sonora, Mexico.
Height: Up to 26 feet.
Nocturnal, 21/2-inch bloom, white/near white flowers that are followed by edible fruit.
Hardy to 25 degrees.

Toothpick Cactus - Stetsonia coryne

Origin: Argentina and Bolivia.
Height: 8 to 30 feet tall.
Blooms: white/near white flowers in late spring.
Hardy above 18 degrees.

Other columnar type cacti include Peruvian Old Man, Old Man of the Andes and Parodia, all of which originate in South America.

CYLINDRICAL-TYPE CACTI

Texas Rainbow Hedgehog - Echinocereus.
Origin: Texas, New Mexico, Mexico.
Height: 12 inches.
Different species have large range of colors from green to yellow, pink, orange and red. Flowers are goblet shape and bloom day and night in mid spring.
Hardy to 14 degrees.

In addition to the cylindrical type, there is a variation thereof known as the cylindrical segmented type. The differentiation comes in the cactus being segmented in pieces.

FLAT-TYPE CACTI

Black Spine Prickly Pear - Opuntia macrocentra
Origin: Arizona, New Mexico, Big Bend and northern Mexico. Height: 4 feet.
Blooms: early summer/red or yellow flowers with red center.
Hardy to 10 degrees.

Irish Mitten - Opuntia vulgaris and Joseph's Coat - Opuntia vulgaris var. variegate
Origin: Argentina.
Height: 36 to 48 inches.
Blooms: yellow flowers in mid spring.

Joseph's Coat -
Pads are variegated.
Hardy to 30 degrees
.

Bunny Ears - Opuntia microdasys
Origin: Mexico.
Height: 24-36 inches.
Blooms: bright, yellow flowers in mid spring/yellow spines.
Hardy to 30 degrees.

Cinnamon Cactus - Opuntia microdasys rufida
Origin: Mexico.
Height: 24-36 inches.
Blooms: bright, yellow flowers in mid spring/ brownish spines. Hardy to 30 degrees.

BARREL-TYPE CACTI

Golden Barrel - Echinocactus grusonii
Origin: Central Mexico.
Height: 24-36 inches.
Blooms: pale yellow flowers in mid summer.
Hardy to 15 degrees brief periods

Devil's Tongue - Ferocactus latispinis
Origin: Coahuila and Nuevo Leon, Mexico.
Height: 12 inches. It gets its name from the wider thorn that grows in the center of all the rosettes.
Blooms: lavender flowers in winter when most barrels flower in summer.
Hardy to 25 degrees.

Goat's Horn - Astrophytum capricorne
Origin: Texas and Coahuila, Mexico.
Height: 10 inches.
Blooms: a dwarf yellow flower with reddish throat. It gets its named from the characteristic shape of the long, curled and flattened spines.
Hardy to 20 degrees.

Plaid Cactus - Gymnocalycium mihanovichii friedrichii
Origin: Argentina.
Height: 1.5-6 inches, low growing solitary cactus.
Blooms: white flowers with reddish throat, 2.4 inches long.
Hardy to 50 degrees.

While these all have a barrel appearance, they're also similar, small-rounded type cacti, with clumping and cylindrical clustering appearance that originate in Mexico.

Texas Prickly Pear - Opuntia engelmannii

Origin: Texas, New Mexico and Mexico. The spines can be painful when encountered, believe me; I had the honors. They have beautiful red, yellow or purple flowers on the pads. They vary in height from a foot to 6-7 feet tall. The pads also vary in width, length, shape and color. Adopted as state plant on May 25, 1995.

Yucca - Yucca (many species)
Origin: Mexico and southwestern United States. Height: 21/2 to 12 feet. The Spanish dagger, Spanish bayonet, soap weed, and Adam's needle bloom white flowers from mid-summer to autumn. Red yucca bloom red flowers from April to August.
Height: 36 to 48 inches.
Both white and red species attract bees, butterflies, and birds. Caution: Use eye protection because of its sharp edges when handling.

Blue Agave - Agave tequilana.

Origin: Mexico.
Height: 4-6 ft.
Foliage: blue-green. It's the base ingredient of tequila, a popular distilled spirit and important economic product to the state of Jalisco, Mexico.

This listing encompasses a sampling of the cacti we've planted in our desert garden. Due to their diversity, it is really a thrill to see the many different species come into bloom at various times throughout the year.

Cacti are among the most unique and fascinating types of plant. They are indeed a great addition in a landscape. A small investment will reward you with many years of enjoyment.
PHOTOS BY ROY COOK/VICTORIA COUNTY MASTER GARDENER
With a growth rate of 1 inch per 10 years, the columnar-type saguaro cactus has a long life span and can reach 15 to 50 feet in height. It is native to the Arizona Sonora desert and blooms a white flower with a yellow center.
The toothpick cactus is a columnar-type cactus that originated in South America. It can reach 8 to 30 feet and boasts white/near white blooms.
The golden barrel cactus resembles its name, appearing squatty and only 2- to 3-feet tall at maturity. It blooms pale yellow flowers in mid-summer.
Another barrel-type cactus, the goat's horn variety originates in Texas and Coahuila, Mexico. It reaches 10 inches high and blooms yellow flowers with red throats. It gets its name from the characteristic long, curled and flattened spines that resemble goat horns.
CACTI VS. SUCCULENTS

The cactus family, Cactaceae, is one of the many families having succulent growth. With about 2,000 species, it originated mostly in the Americas. Other plant families having this type of growth are milkweed, lily and the agave families. Therefore, while cacti are succulents, not all succulents are cacti.

Examples of succulents include:

Ocotillo -
Fouquieria splendens

Blue chalk fingers -
Senecio vitalis

Elephant bush -
Portulacara afra


CACTI VS. EUPHORBIA

Historically evolving from the same ancestral roots, euphorbia is native to Africa and cacti evolved in the Americas. Both groups developed succulent bodies to retain moisture within the plant itself. Both groups have few leaves, if any at all. Euphorbia (spurges) has softly colored bracts that surround subtly defined flowers. Cacti usually have pronounced blooms appearing on the exterior edges of the green stem. A significant characteristic that differentiates the two is a milky, white sap, often caustic, that bleeds from the euphorbia plant when the stems are cut or wounded in comparison to a cactus bleeding a clear or green liquid.


Examples of euphorbia include:

Golden candelabra - Euphorbia lacteal

African milk tree -
Euphorbia trigona

Elkhorn -
Euphorbia lacteal 'Cristata'

Montrose Cereus -
Euphorbia lacteal
The Gardeners' Dirt is written by members of the Victoria County Master Gardener Association, an educational outreach of Texas AgriLife Extension - Victoria County. Mail your questions in care of the Advocate, P.O. Box 1518, Victoria, TX 77901; or vcmga@vicad.com, or comment on this column at www.VictoriaAdvocate.com.