View On Gardening

The Mojave Desert is the least understood American landscape. People unfamiliar with the Mojave Desert can hardly believe the high temperatures and low precipitation that we accept as normal. It’s no wonder there are so few trees that call the Mohave home.

A famous author once said the key to becoming western is getting over the color green. The Mojave will give you much opportunity to test the truth of that statement. But in our cities and yards, trees are essential if we expect to be comfortable in this land of perpetual sun.

Planting trees is a necessary adaptation to human settlement in arid environments. A strong, healthy community forest is built tree by tree, home by home. Tree canopies help to reduce energy demands, reduce water demands, reduce local air temperatures, reduce air pollution, provide habitat for birds, and create beautiful, shady urban environments. Trees have been called “nature’s air conditioner” and “the lungs of the earth.” Their ability to cool and clean the air brings us welcome relief from sun and smog, especially in the concrete-and-asphalt heat islands of our cities. Trees produce life-sustaining oxygen while absorbing pollutants and protecting soil from erosion by wind and water.

Southern Nevada is part of the Mojave Desert, a shrub-dominated landscape. While native trees do exist in our desert, they occur in streambeds and at higher elevations. Low elevation native trees tend to be small, compact, shrubby, and low-water users, perfect for urban landscapes and water conservation needs. Unfortunately, there are not a lot of these natives that make good shade trees. However, there are many other trees available that come from different areas around the world that have similar arid climates.Like our own natives, these trees are low to moderate water users and can add beauty and protection from the sun and wind. Here are just a few examples:

Mulga Acacia (Acacia aneura) – This Australian native is a small, thornless, evergreen tree with a pyramidal to rounded shape. The small leathery leaves vary from dull gray-green to silvery in color. Adorned with small, fuzzy caterpillar-shaped flowers in the spring, small bean pods follow. This hardy plant thrives in full or reflected sun. It prefers not to be over watered, so once established, water deeply but infrequently.

Sweet Acacia (Acacia smallii) – Each spring this tree perfumes the air with masses of fragrant yellow-orange puffball flowers. It is extremely tough, and will thrive in almost any situation, from hot parking lots to turf areas. Its attractive vase-shaped form makes it a popular choice for desert landscapes. It should be kept away from swimming pools, as its seed pods can create litter. It also bears sharp thorns, so provide ample room near walkways.

Shoestring Acacia (Acacia stenophylla) – This thornless, rapidly-growing evergreen tree produces long, willowy leaves that resemble shoestrings dangling in the wind. It is often recommended for use near pools or against walls with reflected heat due to its small number of pods and lack of thorns. Creamy white puffball flowers are produced in early spring followed by long bean pods. This plant is extremely drought tolerant once established.

Bottle Tree (Brachychiton populneus) – An evergreen tree of moderate size that is also native to Australia. The bright green leaves are shaped like arrowheads. Clusters of creamy white, bell-shaped flowers are produced before summer, often followed by woody, boat-shaped fruits which may be a bit of a litter nuisance. Bottle Trees are useful for windbreaks and shade in extremely hot conditions.

Desert Willow (Chilopsis linearis) – This tree is not a true willow, but it has narrow willow-like leaves. In the wild it is often found as a multi-trunk shrub, but you can find them available in nurseries in a tree-like form as well. Gorgeous pink or white orchid-like flowers are present

from late spring into the fall, attracting hummingbirds and bees. Cultivars include a variety of dark purple and vivid pink flowers like ‘Rio Salado’ and ‘Burgundy Lace.’ Extremely tough and resilient, this is one of the best flowering trees the desert produces.

Chitalpa (Coolibah Tree) (Eucalyptus microtheca) This fast-growing tree is one of the most common Eucalyptus planted in the Southwest. The leathery leaves have a distinctive blue-green color and the cultivar ‘Blue Ghost’ has the most consistent blue-gray foliage. These trees can take full sun, reflected heat, strong winds, drought, and modest cold temperatures.

Chitalpa (Chitalpa tashkentensis) – It has large pink, orchid-like flowers produced in terminal clusters primarily during late spring and continuing intermittently into the fall. One of the finest traits is the lack of seed pods for low maintenance gardens. This tree is somewhat brittle and often has awkward branch patterns, but with a little training can be developed into a nice patio tree. ‘Pink Dawn’ and ‘Morning Cloud’ are the two cultivar selections found in nurseries.

‘Desert Museum’ Palo Verde (Cercidium ‘Desert Museum’) – This tree carries genes from the Mexican Palo Verde (Parkinsonia aculeata), the Foothills Palo Verde (Cercidium microphyllum), and the Blue Palo Verde (Cercidium floridum), and combines the best traits of all three. It grows to twenty-feet tall and as wide in three to five years. Large one-inch blooms appear over a long period. Flowering is most profuse in spring, with rebloom possible in summer. It has light green stems and leaves. This is a clean, thornless tree that produces few seed pods.

Chilean Mesquite (Prosopis chilensis) – This fast-growing semi-evergreen tree has a full, wide spreading canopy. Most seedlings produce prominent thorns, but there are many selections of hybrid, thornless varieties including ‘Phoenix’, ‘AZT’ and ‘Rio Salado’. Mesquites should be irrigated deeply and infrequently to encourage deep rooting and to slow top growth.

Honey Mesquite (Prosopis glandulosa) – This deciduous tree has a picturesque structure with sprawling, wide-spreading branches. Its weeping, light-green foliage is similar to the California Pepper, but it can have thorns. A thornless variety known as ‘Maverick’ is available.

These are just a few of the drought-tolerant tree selections for our area. If you would like to learn about more options, stop by your local Star Nursery and pick up a free copy of the Southern Nevada Guide to Tree Selection and Care — Trees for Tomorrow booklet. It is full of great information and pictures of the trees that have proven to do well here in the Mohave Desert.

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