Flowering Trees & Shrubs of the Colorado Desert
Unlike last year in Anza-Borrego Desert State Park and 2016 in Death Valley National Park (as well as Mojave National Preserve), the deserts of California are far from experiencing a Super Bloom this year.
The Anza-Borrego region only received about an inch of rain this year, as opposed to over 7 inches last year. No wonder annual wildflowers are scarce! During our entire trip earlier in April, I only spotted a few desert dandelions and one lone bloom of desert sand verbena, two species known for carpeting the desert with their brilliant flowers in years of abundant rain.
But despite the lack of annual wildflowers, the desert did not disappoint! This year, the blooms are concentrated a little higher off of the ground, on flowering trees, shrubs and cacti. Hiking up washes often produces the best specimens (though I confess, the Palo Verde photo below was taken outside the visitor center!) By the end of our hike to Borrego Palm Canyon, which was all aflower with Desert Ironwood, Desert Willow and Chuparosa, I had collected more flower photos than I had expected! And in the afternoon, while Eric took a break to do some reading and relaxing, I scurried around the campground with my camera to collect a few more photos of commonly encountered plants in bloom, with the goal of providing you, dear readers, with a brief survey of the flora of Borrego Palm Canyon and the surrounding Anza-Borrego Desert!
Blue Palo Verde (Cercidium floridum) Fabaceae - Legume or pea family
A tree of desert washes, the Palo Verde is named for it's green bark ("palo verde" means green stick in Spanish) which not only provides visual interest but also photosynthesizes for the trees, which are drought deciduous. After they have dropped their leaves to conserve water in the heat of summer, the bark takes over energy production. In the spring, the trees are covered in bright yellow blossoms - absolutely stunning!
Desert Willow (Chilopsis linearis) Bignoniaceae - Catalpa family
Despite it's name, the Desert Willow is not a willow (Salix) at all, but related to Catalpas of the Southeastern United States. Its linear leaves and habit of growing in desert washes suggests it may be related to our riparian willows, but one look at the flowers of this shrubby tree will tell you they are nothing like true willows!
Desert Ironwood (Olneya tesota) Fabaceae - Legume or pea family
The largest tree in the Anza-Borrego desert region, Desert Ironwood can grow up to thirty feet tall and live over one thousand years - and yet it is a legume, just like your garden snap peas! (A number of desert trees are in the legume family, including such well-known species as mesquite (Prosopis) and catclaw acacia (Acacia greggii).) Look for this tree growing in the sandy soil of desert washes, and remember to look up; the beautiful lavender flowers that cover this tree in late spring may require binoculars to see!
Ocotillo (Fouquieria splendens) Fouquieriaceae - Ocotillo family
Many people assume that the bizarre vase-shaped bundles of sticks growing across the Colorado Desert are cacti of some sort - but that is not the case at all! The Ocotillo is in fact a woody shrub. It's brilliant scarlet flowers are striking against the desert sky, and are a critical nectar source for migrating hummingbirds. When the rains come, regardless of time of year, the brown sticks burst into lush green growth, covering their 20-foot branches in tiny leaves that may only last a week or two. When conditions dry out, the leaves fall off and the plants once again resemble a bundle of dried sticks. The Ocotillo can go through it's brown-to-green-to-brown cycle several times each year, as dictated by the rains.
Indigo Bush (Psorothamnus schottii) Fabaceae - Legume Family
Quite frankly, this plant doesn't look like much from a distance (see the first photo below). It has small, narrow, grayish leaves, typical of desert plants, and the branches are covered in inconspicuous but highly effective thorns (also typical of desert plants!). But, as I say about the desert over and over: look closer!! The blooms of the Indigo Bush are gorgeous purple pea-like blossoms, definitely deserving of admiration! And when it is in full bloom, robed in purple, it is truly stunning.
Chuparosa (Justicia californica) Acanthaceae - Acanthus family
Appropriately named, Chuparosa means "hummingbird" in Spanish. And these plants are absolutely adored by hummingbirds, resident and migrant alike. The Chuparosa bushes of the Colorado Desert may start blooming as early as December, providing a nectar source at a time when food is scarce.
Creosote Bush (Larrea tridentata) Zygophyllaceae - Caltrop family
Some specimens of this ubiquitous desert shrub may in fact be the oldest living things on the planet. As Creosote Bush ages, the center branches die out, leaving a ring of vigorous growth around the edge. Over hundreds and thousands of years this process of clonal reproduction continues, causing the rings of genetically identical plants to expand over time. Some of these clonal circles of Creosote Bush are estimated to be over 10,000 years old! Also, this plant smells wonderful - just like desert rain! Cup some of the foliage in your hands, give it a rub and see (or smell) for yourself! Though it is often over-looked for more interesting plants, Creosote Bush is well worth a longer look.
Desert Lavender (Hyptis emoryi) Lamiaceae - Mint family
This is another plant that probably doesn't immediately evoke admiration from casual passers-by. Like so many desert plants, its foliage is nondescript: small, gray and fuzzy. The flowers are also somewhat underwhelming, subtle as they are. But the plant's scent is magnificent, and a dead giveaway to its association with the mint family. I couldn't resist stopping to touch and smell the soft gray foliage every time we passed a Desert Lavender plant! The flowers are pollinated by bees, and the plants favor desert washes and alluvial fans.
Common Desert Thorn (Lycium brevipes) Solanaceae - Nightshade family
This is another nondescript grayish desert plant with relatives growing in your backyard vegetable garden! Desert Thorn is a member of the nightshade family, along with your beloved tomatoes, potatoes, peppers and eggplant!
By now, you've also begun to sense a theme of desert plants: small, narrow leaves (often resinous or fuzzy), gray colors, protective thorns, and flowers well-worth hunting for! All of these characteristics are adaptations desert plants have developed to better survive in their harsh environment. Small leaves reduce water loss through transpiration, and the narrow shape reduces the amount of surface area exposed to the sun. Resinous coatings (such as on Creosote Bush leaves) prevents water loss, and pubescence (fuzziness, as on Desert Lavender) provides some shade for the surface of the leaf. Pale colors like gray reflect sunlight, and thorns deter grazers and browsers. Competition is fierce in the desert! Common Desert Thorn, like many desert plants, is also drought deciduous, dropping its leaves to conserve moisture during dry periods.
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| Desert Dandelions, peeking out from beneath a rock near the mouth of Borrego Palm Canyon |
The Anza-Borrego region only received about an inch of rain this year, as opposed to over 7 inches last year. No wonder annual wildflowers are scarce! During our entire trip earlier in April, I only spotted a few desert dandelions and one lone bloom of desert sand verbena, two species known for carpeting the desert with their brilliant flowers in years of abundant rain.
 |
| One lone Desert Sand Verbena bloom |
But despite the lack of annual wildflowers, the desert did not disappoint! This year, the blooms are concentrated a little higher off of the ground, on flowering trees, shrubs and cacti. Hiking up washes often produces the best specimens (though I confess, the Palo Verde photo below was taken outside the visitor center!) By the end of our hike to Borrego Palm Canyon, which was all aflower with Desert Ironwood, Desert Willow and Chuparosa, I had collected more flower photos than I had expected! And in the afternoon, while Eric took a break to do some reading and relaxing, I scurried around the campground with my camera to collect a few more photos of commonly encountered plants in bloom, with the goal of providing you, dear readers, with a brief survey of the flora of Borrego Palm Canyon and the surrounding Anza-Borrego Desert!
Blue Palo Verde (Cercidium floridum) Fabaceae - Legume or pea family
A tree of desert washes, the Palo Verde is named for it's green bark ("palo verde" means green stick in Spanish) which not only provides visual interest but also photosynthesizes for the trees, which are drought deciduous. After they have dropped their leaves to conserve water in the heat of summer, the bark takes over energy production. In the spring, the trees are covered in bright yellow blossoms - absolutely stunning!
Desert Willow (Chilopsis linearis) Bignoniaceae - Catalpa family
Despite it's name, the Desert Willow is not a willow (Salix) at all, but related to Catalpas of the Southeastern United States. Its linear leaves and habit of growing in desert washes suggests it may be related to our riparian willows, but one look at the flowers of this shrubby tree will tell you they are nothing like true willows!
 |
| Beautiful, orchid-like flowers of the Desert Willow |
Desert Ironwood (Olneya tesota) Fabaceae - Legume or pea family
The largest tree in the Anza-Borrego desert region, Desert Ironwood can grow up to thirty feet tall and live over one thousand years - and yet it is a legume, just like your garden snap peas! (A number of desert trees are in the legume family, including such well-known species as mesquite (Prosopis) and catclaw acacia (Acacia greggii).) Look for this tree growing in the sandy soil of desert washes, and remember to look up; the beautiful lavender flowers that cover this tree in late spring may require binoculars to see!
Ocotillo (Fouquieria splendens) Fouquieriaceae - Ocotillo family
Many people assume that the bizarre vase-shaped bundles of sticks growing across the Colorado Desert are cacti of some sort - but that is not the case at all! The Ocotillo is in fact a woody shrub. It's brilliant scarlet flowers are striking against the desert sky, and are a critical nectar source for migrating hummingbirds. When the rains come, regardless of time of year, the brown sticks burst into lush green growth, covering their 20-foot branches in tiny leaves that may only last a week or two. When conditions dry out, the leaves fall off and the plants once again resemble a bundle of dried sticks. The Ocotillo can go through it's brown-to-green-to-brown cycle several times each year, as dictated by the rains.
 |
| Hummingbird (female or juvenile male Costa's, I think) resting in the shade on an Ocotillo branch |
Indigo Bush (Psorothamnus schottii) Fabaceae - Legume Family
Quite frankly, this plant doesn't look like much from a distance (see the first photo below). It has small, narrow, grayish leaves, typical of desert plants, and the branches are covered in inconspicuous but highly effective thorns (also typical of desert plants!). But, as I say about the desert over and over: look closer!! The blooms of the Indigo Bush are gorgeous purple pea-like blossoms, definitely deserving of admiration! And when it is in full bloom, robed in purple, it is truly stunning.
 |
| The royal purple flowers of Indigo Bush |
Chuparosa (Justicia californica) Acanthaceae - Acanthus family
Appropriately named, Chuparosa means "hummingbird" in Spanish. And these plants are absolutely adored by hummingbirds, resident and migrant alike. The Chuparosa bushes of the Colorado Desert may start blooming as early as December, providing a nectar source at a time when food is scarce.
 |
| Juvenile male Costa's Hummingbird, investigating a Chuparosa flower (right by our campsite!) |
Creosote Bush (Larrea tridentata) Zygophyllaceae - Caltrop family
Some specimens of this ubiquitous desert shrub may in fact be the oldest living things on the planet. As Creosote Bush ages, the center branches die out, leaving a ring of vigorous growth around the edge. Over hundreds and thousands of years this process of clonal reproduction continues, causing the rings of genetically identical plants to expand over time. Some of these clonal circles of Creosote Bush are estimated to be over 10,000 years old! Also, this plant smells wonderful - just like desert rain! Cup some of the foliage in your hands, give it a rub and see (or smell) for yourself! Though it is often over-looked for more interesting plants, Creosote Bush is well worth a longer look.
 |
| We placed our tent right beside a beautiful, wavy-limbed Creosote Bush, and were afforded front-row seats to admire it's flowers, foliage and the abundant life it supported (including hummingbirds, Black-tailed gnatcatchers, lizards and antelope ground squirrels!) |
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| The flowers, fuzzy seeds and small, resinous leaves of Creosote Bush |
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| A feisty hummer staking her claim in a Creosote Bush |
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| She was too adorable and so much fun to watch, guarding her territory! |
Desert Lavender (Hyptis emoryi) Lamiaceae - Mint family
This is another plant that probably doesn't immediately evoke admiration from casual passers-by. Like so many desert plants, its foliage is nondescript: small, gray and fuzzy. The flowers are also somewhat underwhelming, subtle as they are. But the plant's scent is magnificent, and a dead giveaway to its association with the mint family. I couldn't resist stopping to touch and smell the soft gray foliage every time we passed a Desert Lavender plant! The flowers are pollinated by bees, and the plants favor desert washes and alluvial fans.
Cheese Bush (Ambrosia salsola) Asteraceae - Sunflower or Aster family
"They" say this bush smells just like cheese; I think it smells like truly foul cheesy feet. But don't let that deter you! (You never know, some people like the way it smells and hate Creosote Bush. To each his own!) Cheese Bush grows in desert washes and on alluvial fans, only reaching a few feet in height. In the dry months, the plants are golden in color; winter rains turn their branches and tiny leaves green. And yes, it really is in the same plant family as your beautiful garden sunflowers and lettuces!
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| Inconspicuous flowers of the Cheese Bush |
Common Desert Thorn (Lycium brevipes) Solanaceae - Nightshade family
This is another nondescript grayish desert plant with relatives growing in your backyard vegetable garden! Desert Thorn is a member of the nightshade family, along with your beloved tomatoes, potatoes, peppers and eggplant!
By now, you've also begun to sense a theme of desert plants: small, narrow leaves (often resinous or fuzzy), gray colors, protective thorns, and flowers well-worth hunting for! All of these characteristics are adaptations desert plants have developed to better survive in their harsh environment. Small leaves reduce water loss through transpiration, and the narrow shape reduces the amount of surface area exposed to the sun. Resinous coatings (such as on Creosote Bush leaves) prevents water loss, and pubescence (fuzziness, as on Desert Lavender) provides some shade for the surface of the leaf. Pale colors like gray reflect sunlight, and thorns deter grazers and browsers. Competition is fierce in the desert! Common Desert Thorn, like many desert plants, is also drought deciduous, dropping its leaves to conserve moisture during dry periods.
NICE!
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