One of the most common plants in our area is the Ocotillo. We love its odd growth habit and beautiful red flowers in the spring, so much so that it has become a common landscaping plant throughout the Southwest. But few people really know what it is. Though covered with large, sharp spines, it is not a cactus. It grows up to 30 feet high, but it is not a tree. So what is it?
Fouquieria splendens, or Ocotillo, is the only member of its family living in our area. Its closest relative is the weird “Boojum Tree” of Baja Mexico. The plant is really nothing but stems which are completely covered with formidable spines.
After rains, bright green leaves, up to 2 inches long, cover the entire plant. The tall, green stems are the Chihuahuan Desert’s Trees.
Ocotillo bloom in the spring, even in dry years, creating one of our area’s most brilliant wildflower shows.
Ocotillo spines are quite possibly unique in the entire plant kingdom – they are made by leaves. When the plant is growing, the first leaves grow on an oversized leaf stalk and midrib. When they die, the leaf stalk and part of the midrib remain behind hardening into the sharp, stiff, and persistent spine that forms the plant’s primary defense against browsing animals. No other plant we know of produces thorns this way.
After the spines are established, tiny buds appear in the space between the stem and the spine. A completely different type of leaf grows from these buds. These leaves have very short stalks, are around 2 inches long, are rather soft, and grow in clusters of two to 12. They appear within 24 to 48 hours after a rain but fall off after a few weeks. Ocotillo may grow new leaves 7 or 8 times a year – a remarkable accomplishment. More amazing still is the fact that even rootless segments of Ocotillo stems produce leaves when watered, and may do so repeatedly. The ability of rootless ocotillo stems to produce new leaves, without receiving nutrients or hormones, repeatedly, appears to be unprecedented.
Along with spiny cacti, Ocotillo stores water in its stems; it uses a remarkably shallow root system to capture water before it can drain or evaporate. These shallow roots, extending no more than 6 inches below the surface are frequently the plant’s undoing as a plant can be easily toppled by erosion. If the root system is damaged, most Ocotillo never recover.
Ocotillo is an important food source for hummingbirds during their annual migration northwards from Mexico to the mountains of the western United States.
White-tailed deer and bighorn sheep eat the flowers, and humans soak the flowers in water to make a refreshing tea. The Tohono O’odham collect Ocotillo nectar, harden it, and consume it as a candy. Apaches dried and powdered the roots and applied it to wounds. Other medicinal uses are reported, but none were ever pervasive. The waxes and resins are sometimes collected and used to polish leather, and the stems are sometimes used as fuel. They make excellent kindling, burning for a long time.
Hummingbirds are the plant’s primary pollinator though carpenter bees are also important. This is surprising because carpenter bees cannot reach the inside of the blossoms, but obtain nectar by boring into the base of the flower from the outside. Nevertheless, crawling around and over many blossoms seems to do the trick. Verdins also appear to contribute to the plant’s pollination.
Ocotillo has always been considered a useful as well beautiful plant. Native tribes all over the Southwest used the stems and fibers to build a variety of domestic structures. By planting stems next to each other in the ground and watering, a beautiful living fence can be made.
The Pima manufactured some of North America’s earliest furniture out of Ocotillo stems dethorned and bound together with rawhide strips. And Pima used Ocotillo decoratively in their gardens, making them the first documented peoples to use native plants in landscaping.
Many building practices using Ocotillo continue today. Every year, countless spring and summer visitors to Big Bend take refuge in the shade of ocotillo ramadas. Visitors to the Barton Warnock Center gardens in Lajitas can enjoy the Palo Verde trees blooming without having to see the parking lot behind them thanks to a living fence. And like the Pima before them, modern homeowners use Ocotillo in their gardens.
Ocotillo typically start blooming in March, but they may bloom repeatedly when there are good rains. Look for them along roads or at lower elevations in the Big Bend area parks. When we are fortunate enough to get rains during the blooming season, you may get to see Ocotillo with flowers and leaves – it is a sight you will likely never forget.
Though one of the most common plants in the Chihuahuan Desert, Ocotillo is also one of the most unusual, and is a primary determinant of the visual appearance of the desert.