Wednesday, March 29, 2017

Plant Profile: Ocotillo (Fouquieria splendens)

The Ocotillo, Fouquieria splendens, is splendid indeed!  Although, some might disagree. 

This seems to be one of those polarizing plants: you either love it or you hate it.  It seems difficult not to form an opinion of this prominent Sonoran desert plant, with its cluster of gangly branches reaching into the clear desert sky like a bundle of sticks in a vase.  (Bonus: this makes it an easy plant to identify!)  My opinion is probably not a surprise: I love this plant!  It demonstrates impressive adaptations for life in the hot desert, and its brilliant red flowers provide a valuable nectar source for hummingbirds on their northern migration.

Ocotillo at Joshua Tree National Park

Desert plants have many different strategies for coping with the hot, dry conditions of their habitat.  Some have small hairs on their leaves and stems, called pubescence, which provide shade for the plants' surfaces; others have waxy coatings on their leaves to prevent water loss.  Most desert plants have very small leaves to minimize surface area exposed to drying conditions.  Many desert plants have succulent leaves and stems for storing water, like the well-known members of the cactus family. 

Ocotillo flowers, perfectly adapted for pollination by hummingbirds.

But Ocotillos are not cacti.  They are technically woody shrubs, albeit oddly-shaped shrubs, in their own family (Fouquieriaceae).  The Ocotillo family consists of 11 species, with Ocotillos being the northern-most species.  (Other species are found across the Sonoran desert, mostly in Mexico.)

The way Ocotillos have adapted to life in the desert is somewhat unique.  For most of the year, these plants resemble a giant bundle of dry brown sticks.  But when the rains come, their brown stems turn green and sprout an abundance of tiny leaves.  The leaves grow quickly, turning the plants completely green within several days of the first rain.  Brilliant clusters of tubular red flowers bloom at the ends of long branches, and the plant's transformation is complete.  When conditions turn dry, the plant drops its leaves and returns to its brown resting state.  With the summer monsoon rains common in the Sonoran desert, the Ocotillo springs to life once again, responding with a second flush of green growth.  Ocotillos can go through this green-to-brown cycle several times each season, dictated entirely by the rains.

Ocotillo, with a naturalist for scale. 
These plants can grow up to 20 feet in height and live for 100 years or more!

The ability to turn green in response to rain is a strategy that allows the Ocotillo to take advantage of prime conditions in the desert, and save its energy at other times.  By shedding its leaves during the dry season, the Ocotillo conserves water that would otherwise be lost through the extra surface area. 

Looking up into hummingbird heaven

Visitors to the desert in the spring will be stunned by this plant and its towering wands of red flowers.  Ocotillos bloom in the spring, and sporadically in the summer as rains allow.  The spring bloom coincides with the northern migrations of hummingbirds, which rely on this plant for food as they make their way across the desert.  Other desert animals, such as Verdins (Auriparus flaviceps), carpenter bees, and antelope ground squirrels (which can climb the branches), feed on Ocotillo nectar as well.

In California, look for Ocotillos blooming between March and May in the Colorado desert.  (The portion of the Sonoran desert that extends into California is known as the Colorado desert.)  Two excellent places to see Ocotillos in bloom (along with a host of other neat desert plants) are Joshua Tree National Park and Anza-Borrego Desert State Park.

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