Ideal Sun Conditions:
Not all succulents are cacti, but all cacti are succulents. The succulent stem, either globose or columnar are built for water storage and minimum evaporation, ribbed or tuberculate (with round nodule or small eminence, as in Mammillaria, and our Panhandle native, Coryphantha missouriensis, the nipple cactus). The ribs and tubercles expand and contract with water availability. The more pronounced the grooves and tubercles, the less water the stem is holding. Likewise, the ribs are well rounded with ample moisture.
Spines, always emerging from areoles, are modified leaves, providing protection from herbivores. Spines also provide shading from the sun and deflection of wind to reduce evaporation even further. Spines vary greatly in color, size and shape. Spines sometimes appear as woolly hair, offering the added protection against nighttime cold, or in combination with spines found in mostly columnar-shaped cacti found in high altitudes from Peru to Bolivia and Argentina, the Oreocereus genus.
If the shape and form doesn't attract, it is certainly their flowers. Cactus have the most beautiful flowers in the world. In some plants, the flowers are even bigger than the plant itself. Cacti flower every year, after reaching maturity, some species several times a year, including the Thelocactus bicolor, var. bicolor, the Glory of Texas native to Presidio, Brewster and Starr counties near Big Bend National Park. One enthusiastic reference mentioned the similarity of the cholla cactus to early roses in appeal – both have thorny canes and a single period of flowering. Driving a stretch of I-40 between Amarillo and Santa Fe one June, I noticed acres of cane cholla, Opuntia imbricata, in full rose-pink bloom – quite a sight.
Growing cactus is similar to growing agave, lean gritty mineralized soil with good drainage and 6 to 8 hours of sunlight for the best blooms. Afternoon shade benefits most plants, but is not required. Cacti prefer acidic water to our alkaline city water, rain water is the best. De-chlorinate a 5 gallon pail of city water by letting it sit in the sun for a day or two, adding one tablespoon of white vinegar or citrus acid to lower the pH if rainwater is not available. Spare the water in fall and winter for better survival or mound the plant to increase soil drainage.
Below is a list of cacti I believe are reliably cold hardy for Amarillo, or down to zero degrees F. Many of these will survive colder temperatures. Populations of Opuntia fragilis grow natively in several locations in Wisconsin on rock outcrops and sandy soils. I am sure this is not a complete list of cold hardy cacti for the Texas Panhandle.
Coryphantha missouriensis, nipple cactus
Coryphantha vivipara, pincushion or ball cactus
Cylindropuntia whipplei, dwarf pencil cholla, plateau cholla
Echinocactus horizonthalonius, Texas blue barrel cactus, perhaps only cold hardy to Zone 7, summer blooming
Echinocactus texensis, Horse crippler
Echinocereus coccineus, Texas claret cup cactus, very showy
Echinocereus coccineus x dasyacanthus Texas rainbow hedgehog
Echinicereus engelmannii, Strawberry hedgehop
Echinocereus fendlerii, Fendler's hedgehog
Echinocereus fendleri rectispinus, pink flowered Fendler's hedgehog cactus
Echinocereus melanacanthus, White spined claret cup
Echinicereus reichenbachii albispinus, white spined lace cactus
Echinocereus rigidissimus, New Mexico Rainbow cactus
Echinocereus triglochidiatus, claret cup cactus, large, very showy
Echinocereus triglochidiatus gonacanthus
Echinocereus viridiflorus, green flowered hedgehog
Escobaria vivipara, beehive cactus
Opuntia engelmannii, Engelmann's prickly pear
Opuntia engelmannii var. linguiformis, cow-tongue prickly pear
Opuntia fragilis, fragile or brittle prickly pear
Opuntia humifusa, devil's-tongue, a SE US cactus (also called O. compressa).
Opuntia imbricata, Cane cactus, tree cactus, cholla
Opuntia kleiniae, candle cholla
Opuntia leptocaulis, Tasajillo, pencil cactus
Opuntia macrorhiza, plains prickly pear
Opuntia phaeacantha major, Santa Fe prickly pear, brown spined prickly pear
Opuntia polyacantha, Hunger cactus, very spiny
Mammillaria heyderi, nipple cactus
Mammillaria meiacantha, pincussion cactus
Pediocactus simpsonii, mountain ball cactus
Use in Garden
Cactus gardens, rock gardens, native plant gardens, xeristrips, xeric and bee gardens are some of the uses for cactus. Large opuntia or cholla cactus can be focal points in xeric gardens. Cactus make excellent container and dish gardens, either solely, or with other succulents.
Remove leaves or other organic debris that blow into the cacti and get caught in the spines.