desert plants

Velvetpod Mimosa – a desert survivor

Velvetpod mimosa

Velvetpod fruit








The Velvetpod Mimosa (Mimosa dysocarpa) is an extremely drought and heat tolerant legume plant that is native to Arizona, New Mexico, and Texas. It blooms during the hottest part of the summer. It occurs mainly along arroyos and washes, 3500-6500 ft. elevation.

The mimosa is a woody shrub that grows three to six feet tall. The branches have large, sharp thorns. The flowers are showy but misleading because you see the flower filaments not the petals. The petals are very tiny and fused together. (See photos here) Fresh flowers are magenta to deep pink, but fade to light pink and white as they age. The leaves are fuzzy.

The pollen is a mild allergen. Butterflies, bees, birds, and moths are the principal pollinators.

After the flowers are pollinated, the fruit is a one- to two-inch-long bean covered with tiny hairs which look like velvet, hence the name. The bean pod is also protected by four large thorns. These beans are a favorite of quails. The plant is a favorite of Coues white-tailed deer in the Santa Rita Mountains of Arizona (source).

The velvetpod mimosa is often used in xeriscape gardens.

The velvetpod mimosa is in the Mimosoideae subfamily of the Leguminosae family (Fabaceae). For some perspective, here is what the Arizona-Sonora Desert Museum says about this plant group:

“Legumes are a very large family of 16,000 species in nearly all of the world’s habitats. Champion drought tolerators, they are most abundant in the arid tropics. Their prevalence in the Sonoran Desert flora (for example, there are 53 legume species in the Tucson Mountains, 8% of its plants) reflects this desert’s tropical origin. North of the Mexican border most of the common Sonoran Desert trees are legumes.”

“The family was named Leguminosae for its fruit, which in most species is a legume (the technical term for bean pod, a single-chambered capsule enclosing what appears to be a single row of seeds that is actually two rows — alternate seeds are attached to opposite halves of the pod). There are three subfamilies with flowers that look very different from one another at first glance, but arose from a common pattern: Caesalpinioideae, Faboideae, and Mimosoideae.”

Some of my other articles about plants in the legume family are:

Mesquite Trees Provide Food and a Pharmacy

Palo Verde Trees Will Turn the Desert Golden

Desert Ironwood with video

Hopbush pretty and poisonous

Hopbush fruitHopbush









Hopbush (Dodonaea viscosa) is in the soapberry family (Sapindaceae) and is known by about 50 different common names. Hopbush is related to the Western Soapberry tree (see article). You can see many specimens on the grounds of the Arizona-Sonora Desert Museum.

ASDM describes this plant as “…a multi-trunked, evergreen shrub typically 5 to 7 feet (1.5-2.1 m) tall, occasionally to 10 feet (3 m), with bright green foliage. Inconspicuous clusters of small, greenish flowers are followed by showy winged fruits resembling hops on female plants. Flowering and fruiting are variable but mostly in summer and fall.” See some good photos here (where it is called Hopseed bush). See also a great photo from Arizona State University of many bushes in the Superstition Mountains northeast of Phoenix at about 3,000 elevation.

The fruit or seed pods contain just three or four seeds. These winged-pods start out green, then with age, turn a creamy color, followed by a red tinge and finally turn brown when dried out. The fruit is toxic because it contains saponin a compound that tastes like soap.

ASDM: “In the Sonoran Desert region, Hopbush occurs from central Arizona to Sonora and Baja California, from 2000 to 5000 feet (600-1500 m) elevation, always at the upper margin of the desert and often in acidic soils. The same species occurs in warm regions worldwide, even Australia. Exceedingly few plant species have such a wide distribution.”

Hopbush fruit has been used as a substitute for real hops when brewing beer in Australia. True hops, Humulus lupulus, is in an unrelated family.

The Seri people of the southwest used the plant medicinally for a variety of purposes (but sources are not specific). It was also used to stimulate lactation in mothers, as a dysentery treatment, to cure digestive system disorders, skin problems and rheumatism in Africa and Asia. In New Guinea, people use it as incense for funerals.

The wood is extremely tough and durable. In New Zealand, where it is the heaviest of any native wood, the Maori have traditionally used it for making weapons, carved walking staves, axe-handles, and weights on drill shafts. Hopbush is also used by the people from the western part of the island of New Guinea, Southeast Asia, West Africa and Brazil for house building and as firewood. Its leaves may also be used as plasters for wounds. (Source)

“The bark is sometimes used in poultices for swellings and headaches and is added to baths. The leaves have pain-killing, wound healing and diaphoretic (sweat-promoting) qualities as well as being astringent and useful for skin rashes, toothache and sore throats. A decoction or infusion can be made from them and the liquid applied to affected areas of the skin.” (Source)

The U.S. Department of Agriculture says:

The fibrous spreading root system, rapid growth, and spreading canopy make D. viscosa an effective soil stabilizer which is particularly useful in controlling gully and coastal dune erosion. It is drought tolerant and has the ability to withstand wildfires. D. viscosa shrubs are somewhat shade tolerant and suitable for riparian and restoration projects. They are also very wind hardy and useful as an in-field windbreak system.

D. viscosa is an aesthetically pleasing plant. It has lush green foliage and deep red capsules that make it pleasing to the eye. D. viscosa may be used as a hedge, specimen plant, or maybe a small patio tree. It is ideal for xeriscape gardens.


Western Soapberry trees often buzz with activity

Western soapberry fruitThe Western Soapberry tree (Sapindus saponaria var. drummondii) is a slow-growing deciduous tree with a dense canopy of dark green compound leaves. It occurs throughout the southern Great Plains, extending into eastern Arizona and the Mogollon Rim. In Arizona it typically grows 15 to 20 feet high, but can get up to 50 feet high in deep soil. Varieties of soapberry are also native to Hawaii, Mexico, South America, New Caledonia, and Africa.

The tree produces copious clusters of tiny white flowers in the spring and early summer. These flowers attract hundreds of pepsis wasps and bees. (see Pepsis wasps have the most painful sting and Desert Bees ) You can see two of these trees at the Arizona-Sonora Desert Museum near the Prairie Dog exhibit. According to ASDM, the Western Soapberry is the larval food plant for the Soapberry Hairstreak butterfly. (See butterfly images) See more photos of the flowers, fruit and seeds here.

Upon pollination, the flowers turn into a whitish-yellow, grape-sized fruit which is both poisonous and unpalatable. The fruit turns darker, golden to red, with age. The fruit produces a single large seed.

The fruit is poisonous because it contains saponin, a compound that tastes like soap and can be used as soap when mixed with water. This mixture was also used as floor wax and varnish according to the US Forest Service. The mixture can cause dermatitis in some people.

Native people made necklaces and buttons from the round dark brown seeds.

According to TexasBeyondHistory:

More than one group found the wood to be useful for making arrows. The Comanches fashioned arrows from the stems of western soapberry. The Papago used the wood of soapberry to make the foreshaft of their arrows.

The bark was peeled off of slender green soapberry stems, which then were straightened and dried. The arrow maker then split the tip of the dried shaft, inserted the small stone arrow point, and tied it with wet sinew. The account notes that a gum from brittlebush (Encelia farinosa) was utilized to cement the tip to the shaft; however, brittlebush does not grow on the Edwards Plateau or eastern Chihuahuan Desert. We do not know what type of gum may have been used in our region. The arrow artisan would make the main arrow shaft from soaptree yucca (Yucca elata) or from common reed (Phragmites communis). Common reed grows throughout the area, but on the Edwards Plateau, Thompson yucca flower stalks would have been used instead of the soaptree, which grows further west in the Trans-Pecos region. A hole two-inches deep was hollowed into the end of the arrow shaft so that the foreshaft (fashioned of soapberry) could be inserted. Once inserted, sinew was wound tightly around the entire length of the hollowed out area.

The Western varietal name for this plant, drummondii, is, according to the Lady Bird Johnson Wildflower Center, “named for Thomas Drummond, (ca. 1790-1835), naturalist, born in Scotland, around 1790. In 1830 he made a trip to America to collect specimens from the western and southern United States. In March, 1833, he arrived at Velasco, Texas to begin his collecting work in that area. He spent twenty-one months working the area between Galveston Island and the Edwards Plateau, especially along the Brazos, Colorado, and Guadalupe rivers. His collections were the first made in Texas that were extensively distributed among the museums and scientific institutions of the world. He collected 750 species of plants and 150 specimens of birds. Drummond had hoped to make a complete botanical survey of Texas, but he died in Havana, Cuba, in 1835, while making a collecting tour of that island.”

Stinging Spurge – the Mala Mujer of Arizona and Sonora

Stinging spurgeMala mujer leaf









Stinging Spurge (Cnidoscolus angustidens), commonly called Mala Mujer (bad woman) is a plant to be wary of. This plant grows in desert uplands of southern Arizona and northern Sonora. According to Fireflyforest, it is especially common on rocky slopes in the Santa Rita Mountains. There are some of these plants growing at the Arizona-Sonora Desert Museum. A closely related species, Cnidoscolus texanus, occurs in Texas, Arkansas, Kansas, Louisiana, and Oklahoma. Another related species, Cnidoscolus stimulosus, is native to the southeastern United States from Louisiana to Virginia

Fireflyforest: “The attractive, maple-like leaves are dark green, heart-shaped, lobed, toothed, and covered in white polka dots. A stinging hair is at the center of each white dot, so do not touch the leaves. Stinging hairs are also present on the stems and at the base of the flowers.” The male flowers are five-petaled about 3/4 inch wide. Small female flowers occur at the base of male flowers. This plant commonly grows two to three feet high.

The stinging hairs can cause extreme pain and contact dermatitis. They can easily penetrate your skin. The secretions of the plant, a milky sap injected by the stinging hairs, can cause an intense burning sensation due to their highly acidic pH. A paste made of baking soda and water is an effective first-aid treatment. But the effects can last for days.

If you commonly hike mountain trails in southern Arizona, learn to recognize this plant. Don’t be taken in by its pretty flowers. Don’t touch this plant.

Despite its nasty nature, you can find online sites promoting using this plant in your garden and growing it for its seed oil.


Sacred Datura – pretty, poisonous, and hallucinogenic

Sacred Datura (Datura wrightii), widely known as Jimson Weed, is blooming and will continue into late summer. This perennial plant occurs from central California to Texas and Mexico and into northern South America.

Datura 2

The pretty, lily-like white flowers can reach up to six inches long and three inches wide. The dark green leaves are sticky and can give off an unpleasant odor when crushed. The whole plant can reach five feet tall and several feet wide.

Datura produces a golf-ball sized, melon-like fruit which is covered with spikes, hence its other name “Thorn apple.”

Datura 3

Datura has a large tuberous root which allows the plant to survive cold winters that may kill the above-ground foliage.

The Arizona-Sonora Desert Museum warns:

“All parts of these plants contain numerous toxic alkaloids. One of them is scopolamine, a common ingredient in cold and nausea remedies. Shamans in various cultures have ingested datura to induce visions. This is one of the most dangerous plants used for this purpose, because not only do individual plants vary in potency, but humans also differ in their tolerance to the toxins. Despite widely-published warnings, every year a few people suffer life-threatening poisoning from eating this plant; some of them don’t survive.”

ASDM also notes: “This beautiful plant is a useful ornamental if there is sufficient space for its large size and one is willing to put up with its winter disappearance below ground. Hawkmoths pollinate the flowers and lay eggs on the foliage. The caterpillars (called “hornworms” in this family) incorporate the plant’s toxins into their own tissues and become toxic to their potential predators.”

James W. Cornett, in his book “Indian Uses of Desert Plants” also warns of the toxicity and notes many other uses for this plant.

“A paste made from the leaves and stems was applied to broken bones and swollen joints to reduce or eliminate pain. Inhalation of fumes given off by burning or boiling the leaves was effective in relieving respiratory aliments.”

Patches of Sacred Datura grow in several exhibits at the Arizona-Sonora Desert Museum. The animals in these exhibits leave it alone and so should you.

Learn about more desert plants:

A Desert Christmas cactus

Agave, a plant of many uses

Arizona Passion Flower

Arizona Wild Cotton

Brittlebush and chewing gum

Can You Get Potable Water From a Cactus?

Chiltepin peppers, spice and medicine

Creeping Devil Cactus

Creosote Bush, a Desert Survivor

Data presentation in Santa Catalina Mountains plant study misleading

Desert Tobacco, a pretty but poisonous desert plant Desert Ironwood with video

Desert Mistletoe Edible Desert Plants – Barrel Cactus Fruit

Jojoba oil, good on the outside, bad on the inside

Joshua Trees of the Mohave Desert

Limberbush or blood of the dragon

A London Rocket in my yard

Mesquite Trees Provide Food and a Pharmacy

More on Mesquite

Oak trees of the Sonoran Desert Region

Ocotillos and the Boojum

Palo Verde Trees Will Turn the Desert Golden

Saguaro Cactus Icon of the Sonoran Desert

Should the Acuna cactus receive Federal protection?

Spectacular flowers of the Red Torch Cactus

The Old Man and the Totem Pole

Tucson invaded by popcorn flowers

Yuccas provide food, fiber, and soap

Arizona’s Wild Cotton

Commercially-grown cotton is one of Arizona’s five “Cs” (Cattle, Copper, Citrus, Cotton and Climate) and is important to the economy. There is a wild cotton plant, native to the Sonoran Desert, which some think may be a progenitor of the cultivated product: Arizona Wild Cotton (Gossypium thurberi), also called Desert Cotton and Thurber’s Cotton.

AZ wild cotton bush

This plant is relatively common in the foothills around Tucson and can be seen in the “Grasslands” exhibit at the Arizona-Sonora Desert Museum. It can grow up to 10 feet tall.

In the spring, Arizona Wild Cotton will produce pretty, white, cupped flowers which may have spots of pink; The flowers, which are one to two inches in diameter, turn fully pink to lavender with age. (That is the red seen in the first photo.)

AZ wild cotton flower

After the flowers are pollinated, mainly by bees, they turn into a hard-shelled fruit, or bolls, about a half-inch in diameter. With age, the bolls open to reveal white to grayish fibers.

AZ wild cotton fruit

You can see more photos from The Firefly Forest, the last of which shows how many of the leaves turn scarlet before falling off.

Because this wild shrub is a close relative to cultivated cotton, it shares several of the same pests such as the Pink Bollworm. It is used as a larval food plant for the royal moth (Citheronia splendens sinaloensis).

According to
“In the 1930’s attempts were made to eradicate this plant from the mountains and foothills of southern Arizona. The reason being that a weevil (small beetle) that feeds within the developing bolls was thought to be the same as the infamous Cotton Boll Weevil. Later, taxonomic studies by Dr. Floyd Werner determined that the Thurber Weevil was not the same and that it did not affect cultivated cotton. Luckily the eradication efforts failed and the plant has returned to be a common, attractive plant. Thurber’s Cotton makes a nice addition to xeriscape gardens and can be pruned to become a ‘cotton tree’.”

Tinctures made from the bark of cotton plant roots are claimed to relieve a variety of conditions, see WebMD.

Check the Article Index page for more about the Sonoran Desert.

Tucson invaded by popcorn flowers

They were inconspicuous at first, but soon they formed a fuzzy blanket.

Last month, popcorn flowers (Cryptantha) invaded my yard and those of my neighbors to form a prickly, grayish-green groundcover (see photo below).  There are 35 species of popcorn flower in Arizona and I think the one in my yard is the Narrow-leaf popcorn flower (Cryptantha augustifolia). But if any botanists have a different opinion from looking at the photos, please write a comment.

These plants are small (2″ to 10″ high) grayish-green, fuzzy, with tiny (1/8″) white, five-petaled flowers.  The leaves are narrow, grayish, hairy, and up to 1.5″ long.  The plant is uncomfortable to touch because of the hairy bristles.  The plants are in the Forget-me-not or Borage family.

This annual plant blooms from February through June. I had not noticed them in my yard before, but this year there are hundreds.  Apparently the plants germinate in the Fall, then bloom in February and March.  Seeds can lie dormant for many years, just waiting…waiting for the right conditions. Then they explode.



Ocotillos and the Boojum

ocotillo1-245x300For most of the year, the ocotillo (Fouquieria splendens) looks like a spiky, dead stick, but come rain and it leafs out profusely.  The ocotillo family consists of 13 species confined to the warm and arid regions of North America.

The ocotillo common to Arizona and Sonora can leaf out completely within 48 hours of a rainfall.  If there is no additional rain, the leaves turn yellow and fall off within a few weeks.  This cycle can be repeated many times during the year.  When the leaf falls off, the petioles (leaf stalks) harden to form spines.

The ocotillo is classified as a woody shrub that can get up to 20 feet high.  It flowers in the spring whether or not it has leaves.  The bright red to red-orange flowers are pollinated primarily by hummingbirds, but also by insects such as carpenter bees.  Ocotillo flowers are frequently the only abundant flower in dry years.

The flowers, when soaked in cold water make a refreshing drink, and the flowers can be used to garnish salads.  They usually have a slightly sour taste like lemon.  Ocotillo stems are used for house walls, ramada roofs, and fences.  Ocotillo stems often take root creating a living fence.


If you look closely at the second photo, you may see that parts of the stem are green.  This allows the plant to carry on photosynthesis even when leafless.  Ocotillos also have the ability to idle their metabolism to survive long periods of drought.

Ocotillos grow from low elevations up to about 6,000 feet.  At higher elevations they prefer to grow on limestone, a fact valuable to geologists.  The reason for the limestone preference is that limestone has a higher specific heat than other rocks and thus offers more frost protection to the plant.  At hotter, lower elevations, ocotillos grow better in granite because granite weathers into a gravelly soil that retains moisture.

Boojum1-201x300The boojum (Fouquieria columnaris) is a relative of the ocotillo.  Boojums are endemic to Baja California and can grow up to 60 feet high.  Unlike the ocotillo, the boojum is a succulent. The stem stores water.  The stem produces hundreds of non-succulent branches that have spines.  Leaves sprout any time moisture is available.

Boojums generally grow in winter and sprout fragrant flowers.  The plants can live up to 100 years.

Boojums are pollinated by insects, but it seems that different insect species do the pollination in different years.

According to the Arizona-Sonora Desert Museum, the boojum got its name as follows:

“The English vernacular name comes from Lewis Carroll’s The Hunting of the Snark, a fictitious account of exploration of far-away places. The book contains a mythical creature called the “boojum” which inhabited distant shores. When explorer Godfrey Sykes encountered the plants growing on the desolate Sonoran coast in 1922, he was reminded of Carroll’s story and dubbed them boojums.”

Ocotillo-like plants grow in Madagascar, but these are in a different family, the Didiereaceae.  These plants grow much larger and have succulent leaves.  That they look like ocotillos is an example of convergent evolution, structure follows environmental conditions.

The Creosote Bush, a Desert Survivor

The Creosote bush is a plant of extremes: it was a widely used medicinal plant; it is the most drought tolerant perennial in North America, and it may be the oldest living plant.

Creosote (Larrea tridentata), also known as greasewood, is the most common shrub in three of the four north American deserts. It is too cold in the Great Basin Desert of Nevada, but it thrives in the Mojave, Sonoran, and Chihuahuan deserts. Creosote is an evergreen shrub, commonly up to six feet tall or taller, that has tiny green leaves, yellow flowers, and grey-fuzzy fruit. It flowers several times a year depending on rainfall.

The leaves are shiny due to a waxy coating that prevents water loss. Rain, however, volatilizes that waxy coating which then produces a distinct, camphor-like odor which some desert dwellers call the smell of rain. You can often experience the odor by cupping some leaves in your hands and blowing on them. There is enough moisture in your breath to volatilize the wax.


The creosote is the most drought-tolerant perennial plant in North America. Its hardiness can be seen as one travels from the relatively wet Tucson area to dry Yuma which averages about 2″ per year. Along that traverse, perennial plant species decrease from about 300 here to about 12 near Yuma. Going south along the Colorado River region, dry valleys contain only creosote and bursage, and in some places, even bursage disappears. The creosote can survive two years without rain. It may drop leaves and branches to preserve water and nutrients in the root crown.

There is a legend that creosotes inhibit growth of any other plants around them. Not exactly. The roots will excrete a substance which inhibits growth of bursage, its main competitor, and it will also inhibit germination of its own seeds so competing new creosote bushes will not grow nearby. But, the creosote is an important nurse plant for small cacti and many other plants.

Some creosote bushes in the Mojave Desert are thought to be about 11,000 years old. The branches of the plant will live several centuries and die out, but the root crown produces new branches in a ring around the original plant. With time, this ring expands outward as old branches die and new branches take their place, and eventually become separate bushes which are clones of the original seed. If the prevailing wind is especially strong, only the clones downwind of the parent plant will survive, forming a line of plants instead of an expanding ring. If you’ve ever tried to kill a creosote bush by cutting back the branches, you know that it will grow back within a few months.

The leaves of the plant apparently taste bad. Only the Jackrabbit is known to eat the leaves, and then, only when there is nothing else available. However, “More than 60 species of insects are associated with this plant, including 22 species of bees that feed only on its flowers. Many are specific to it, such as the creosote katydid (Insara covillei) and creosote grasshopper (Bootettix argentatus), which are so camouflaged that they are very difficult to find. Lac insects (Tachardiella larreae, a scale insect) can occasionally be found on its stems. Desert peoples used its sticky secretions as a multipurpose sealant and glue. Ball-shaped leafy galls are common on stems. They are produced by the creosote gall midge (Asphondylia); larvae of these small flies live in the protective mass of tissue. The Seri smoked the galls like tobacco.” (Dimmitt,2000).

Dimmitt also notes that the creosote bush “is the single most widely-used and frequently-employed medicinal herb in the Sonoran Desert. One of its medicinal names is chaparral tea, though it does not grow in chaparral. The Food and Drug Administration has considered banning its sale based on a couple of deaths attributed to drinking it. But innumerable native peoples and some knowledgeable ethnobotanists drink large quantities of it for a wide variety of ailments with no detectable ill effect (other than gagging from its awful taste). Its antioxidant properties were used in foods and paints through the 1950s and are now being evaluated as anti-cancer agents.”

Various sources report that teas made from the leaves and small twigs cure of fever, influenza, colds, upset stomach, gas, gout, arthritis, sinusitis, anemia, and fungus infections (CRC Ethnobotany, June 12, 1999). Creosote also has antimicrobial properties, making it a useful first aid antiseptic. It is also beneficial in the treatment of allergies, autoimmune diseases, and Premenstrual Syndrome (Moore, 1989, p.29). Creosote serves as an analgesic, antidiarrheal , diuretic, and emetic. Creosote can be used on the skin as a tincture or salve. There is some evidence that prolonged use (especially from creosote concentrated in tablet form), can cause liver or kidney damage.

Creosotes originated in South America where there are five species of Larrea. It is somewhat of a mystery how creosotes got here from South America since there is no suitable intervening habitat for thousands of miles.

And no, this is not the creosote used for wood preservation; that’s a petroleum product.


CRC Ethnobotany, June 12, 1999

Dimmitt, Mark, 2000, in A Natural History of the Sonoran Desert, ASDM Press.

Moore, 1989, Medicinal Plants of the Desert and Canyon West. Museum of New Mexico Press, Santa, NM.