Ocotillo

I love the desert, and in particular, the diversity of plant and animal life that has evolved to live in that harsh environment. One of my favorite desert plants is the ocotillo, also known as Jacob's staff, coachwhip and vine cactus. The ocotillo is found in the deserts of the southwestern United States and northern Mexico. It is a V-shaped shrub with spiny, whip-like stems that branch upwards from its base. It can grow as high as 20 feet and is found in open, rocky, well-drained, slopes and plains up to 5,000 or 6,000 feet in elevation. Below is a solitary ocotillo near the mouth of Borrego Palm Canyon in Anza-Borrego Desert State Park.

Below is another ocotillo near Eagle Mountain (south of the 1-10 freeway, east of Chiriaco Summit).

The ocotillos, below, were growing together in a small area near Eagle Mountain.

The red flowers at the tips of the stems are tubular, 1/2 to 1 inch in length.

The flowers appear in clusters about 10 inches long, from March through June, or perhaps later, depending on rainfall. Hummingbirds and carpenter bees are the major pollinators and the spring hummingbird migration is timed to coincide with the flowering period as the nectar is crucial as a source of energy to the migrating hummingbirds.

The ocotillo has two types of leaves. The primary leaves are produced when the stem grows. Those leaves have a stout center midrib which form spines after the leaves are shed. The secondary leaves grow rapidly in response to rainfall, sometimes within 24 hours, then wither quickly after the soil dries out. Therefore, the ocotillo is always spiny, but is leafless most of the year. The secondary leaves are oval, about two inches long, and grow from the axils of the spines (the angle between the stem and the spine). Below is a close-up of the secondary leaves. These pictures were taken in March 2009, shortly after some rainfall, and I have never seen secondary leaves so large, plentiful and green.

Although difficult to see because of the secondary leaves, some spines are visible in the picture below.

The ocotillo below has secondary leaves that are red. It was photographed on the Chuckwalla Bench in December 1991.

Note that there are tinges of green on some of the leaves. I don't know whether it was green and turned red, or vice versa, or whether the leaves never turned green.

The picture below is of an ash-throated flycatcher resting on an ocotillo stem in Organ Pipe Cactus National Monument in March 2008. Note that the flowers have not fully bloomed and the stem has no secondary leaves, exposing spines.

Ocotillos grow slowly, reaching maturity in 60 to 100 years. Some are 150 to 200 years old.

The best source of information for this post was the Living Desert website. I also used the Desert USA website and Wikipedia, Ocotillo.