Cool-looking cactus for hot summer gardens

Statuesque, decorative, edible, capable of creating a fortress or fence, fire-resistant, bee-friendly, deer-resistant, requiring little to no water and with often flamboyant flowers, prickly pear cactus (Opuntia) can perform many functions in gardens.

The most well-known prickly pear cacti are the almost spineless hybrids (Opuntia ficus-indica and Opuntia robusta), developed and grown by the renowned local plant breeder, Luther Burbank. He widely promoted nearly 60 varieties that he developed from 1906 to1925 as valuable fodder for cattle in desert regions. But it didn’t pan out. His hybrids needed irrigation or grew too slowly to recover from grazing. After his death, his widow Elizabeth selected seven to save. Most still grow at the Luther Burbank Home and Gardens in downtown Santa Rosa.

Besides these survivors, there are many old statuesque specimens growing around old houses in the area and at the old California missions and historic adobe houses throughout the state. The species Opuntia ficus-indica has been cultivated in Mexico for its edible pads and fruit for hundreds of years. Opuntia cactus are native to North America, Mexico and South America. There are about 90 species in America, some very large and others small. Most are found in Texas, Arizona and New Mexico, plus a few in the southeastern U.S. and other states.

Some are extremely cold hardy; others tolerate heat and humidity and some prefer frost-free climates. The amount of spines varies greatly, with some cacti covered with large, very sharp spines and others bearing short fuzzy-looking glochids (small, hairy barbed spines) that can have a decorative effect (look, but don’t touch!). Pad shapes and sizes vary greatly. Many are oblong, but they also can be circular or feature scalloped edges. Pad colors come in green, gray and even purple. Their flowers are numerous and showy and come in yellow, red, pink, salmon and orange. There are a number of selections and cultivars in the nursery trade. Luther Burbank’s hybrids tolerate cold down to about 20 degrees.

Easy to grow in Sonoma County

Opuntias are easy to grow in our area. While some require very well-drained soil, as long as water does not pool many tolerate a variety of soil types. They require little, if any, irrigation once established. If pads begin to wither, water about once a month. Most grow best in full sun, but a few species tolerate semi-shade.

The largest types develop a woody trunk over time and can reach heights of about 8 feet tall and even taller. Most, both large and small, grow more wide than tall but can be pruned by carefully removing branches with a saw, knife or pruners.

There are a number of easy-to-manage smaller species and cultivars that range from 1 foot to 4 feet tall. Over time, some of the smaller varieties’ main trunks can deteriorate. Just cut off branches and replant them to replace the old plant. Pads are simple to propagate as well. Cut at the base, allow to callus for a week or so and plant one-third of the base in soil. Don’t water the pads until they’ve rooted.

Small and large specimens make good companions with plants like yuccas, agave, hardy aloe and some of our shrubby native manzanitas. Summer-dry bulbs like our natives but also daffodils, narcissus, ixia, sparaxis and belladonna lilies are a great addition to the ensemble. Opuntia also grow well in pots. These should be placed judiciously so as to avoid contact.

Opuntias with spines need careful placement. Many so-called spineless varieties still have some glochids. The spines and the more innocent-looking glochids both constitute a hazard to people and pets. Spines are more easily extracted from skin, but the glochids that often appear soft and fuzzy have tiny barbs and are more difficult to remove. Strong tape, like packing tape, placed over the skin is a good way to do this. Protect yourself with tongs and leather gloves.

Flowers and fruit

The pads are not leaves but photosynthesizing stem-segments called cladodes. Areoles, or growth points, dot young pads in an ordered pattern. As the pad matures, spines and glochids grow from these points. Flowers also grow from areoles but are mainly clustered near or on the pad edges. Each pad often has multiple very showy flowers. When the plant is in bloom in early or midsummer, blooms are incredibly showy and are native bees’ favorites. Many of the flower bases develop fruit, called tunas. They vary greatly between species and cultivars in size, flavor, seediness, edibility and the amount of spines.

Some of the better fruits may be a fat 4-inch-long yellow, red or purple cylinder and have flavors of watermelon, strawberry, melon, banana and citrus. Fruit is made into juice or cooked down to make jelly or candy. Not all varieties produce fruit that is edible or worth harvesting. Fruit should be harvested ripe as they do not sweeten further off the plant. Most fruits have glochids on the exterior and require care in harvesting and removal before processing or eating. Fruits are usually peeled.

Pads are called nopales and are best harvested when young before the oxalic acid content increases. Cut them at the base where they attach to a lower pad. They can be harvested multiple times a season. Glochids must be removed before eating. Pads are often peeled.

A good cultivar that’s easy to place in gardens is the purple-padded, cold-hardy Opuntia violacea (1.5 feet tall) from Cactus Jungle. It has gray-purple pads and abundant bi-colored yellow and red flowers. Opuntia santa-rita ‘Tubac’ grows to 4 feet tall and has beautiful pads that turn from blue-gray to purple and have showy yellow flowers. A smaller purple-padded, crimson-flowered opuntia is O. x basilaris ‘Baby Rita.’ It needs well-drained soil and may need protection from rain in winter. The most readily available of Luther Burbank’s selections is Opuntia ficus-indica ‘Burbank’s Spineless.’

Kate Frey’s column appears every other week in Sonoma Home. Contact Kate at: katebfrey@gmail.com, freygardens.com, Twitter @katebfrey, Instagram @americangardenschool

Kate Frey’s column appears every other week in Sonoma Home. Contact Kate at: katebfrey@gmail.com, freygardens.com, Twitter @katebfrey, Instagram @americangardenschool