Here's how to choose the right trees for your Tucson backyard

Fast-growing shade trees for your Tucson yard

We live in impatient times, and when we decide we want a tree in our yard we want it to grow quickly so we can enjoy its shade. There are quite a few local trees that grow fast, as well as some that are non-native. However, fast-growing trees come with some caveats.

First, while many of our native trees grow fast if watered a lot, it may not be the wisest course to take. Watering a tree too much can lead to the crown developing faster than the roots, and the wood being weaker than it should be. Both can spell problems once the tree is larger and the branches are heavier. Trees that have been over-watered can suffer wind damage and break off branches more easily. They can even be uprooted by winds and storms.

There’s also the question of water use. You may be willing to give that little tree extra water for a couple of years, but how about when it’s 30 feet tall? It’s best if the tree you plant gets used to our climate, so it can adapt and survive as it grows to full size.

I’ve put together a short list of some fast-growing trees that do well in our climate. There are some varieties in size, so hopefully you can find a tree for your space. Whichever one you choose for your yard, make sure you follow watering guidelines for trees in Tucson.

Mesquite (Prosopis spp): We have three native species of mesquite in our area; velvet mesquite (P. velutina), screwbean mesquite (P. pubescens) and honey mesquite (P. glandulosa). The screwbean mesquite is slower growing and not as tall as the other species. Velvet and honey mesquite can grow up to 25-30 feet tall. They have a spreading shape which provides great shade, are winter-deciduous, and are quite thorny. They thrive in our desert and will not need supplemental water once established.

Desert willow (Chilopsis linearis): One of my favorite trees, desert willows are native to our riparian areas. They may need some supplemental water in hot, reflected sunny urban areas. Horticultural varieties from local growers provide a number of beautiful bloom colors, including light violet, hot pink and deep pink-red. They’re great wildlife trees and have no thorns. They are deciduous in the winter.

Arizona ash (Fraxinus velutina): This is another one of our native riparian trees. It will look best with some supplemental watering. It grows to 50 feet in height, so it will need lots of room. Don’t stake it if you plant one, and don’t trim the lower branches as the bark can become sunburned. It’s also thornless.

Blue palo verde (Parkinsonia florida): This large palo verde tree can grow to 30 feet tall and wide. It likes our hot summers and has gorgeous yellow flowers in the spring. Birds love it for habitat and nesting. It’s extremely drought-tolerant and can take reflected heat, but don’t forget to leave it plenty of room to grow.

Shoestring acacia (Acacia stenophylla): This lovely upright delicate tree is native to Australia. It’s drought-tolerant and a fast grower, reaching to 30 feet. It’s evergreen and thornless, and its long graceful leaves hang like tendrils. It also has creamy puffball-like flowers through the fall and winter. Make sure you move the watering to the outer margin of the dripline so that roots grow outward to stabilize the tree.

‘Red push’ pistache (Pistacia atlantica x integerrima): This horticultural hybrid grows as a single-trunked tree and does not produce nuts. Pistache trees are originally from China. This particular tree has spectacular crimson fall leaves and is winter deciduous. During the summer it has a nice thick leaf canopy. It will need some supplemental water.

Chaste tree (Vitex agnus-castus): This tree originates in Southern Europe, and is fairly drought-tolerant. It has lovely purple flowers which smell nice and attract pollinators. It has a nice shady canopy with lush green leaves, and is deciduous in the winter. It’s not very large, growing only to 15-20 feet or so, but is a very nice small shade tree. It produces some litter, but has no thorns. It will need supplemental water.

Shrubs and small trees to create privacy in your Tucson yard

Sometimes you want to make your garden a private retreat. In fact, one principle of landscape design is that a garden is defined as an enclosed space. While walls and fences can enclose your garden, many people prefer to have a more natural look, particularly if they want to blend their garden in with their surrounding landscape.

A great way to do this is to use plants to delineate your garden space. The plants I’ve chosen here are evergreen and the fast growers will give you privacy within a couple of years. The slower growers will take a few years, but are worth waiting for.

Fast growers (non-thorny)

Hopseed (Dodonaea viscosa): This shrub is native to many parts of the world, and has narrow bright green leaves. It makes for a great informal hedge, and can grow to the size of a small tree. You can prune it (but don’t shear it like a formal hedge) to the shape you want, but make sure you leave enough space for it (at least 6 feet of width and 8 feet of height).

Texas rangers (Leucophyllum spp):These plants are near-natives from the Chihuahuan desert, so they’re drought tolerant and very hardy. There are a number of species and varieties, so make sure you investigate their final size to ensure you will get the look you want. If you choose the correct plant, you will not need to prune them, and after establishment they should not need additional watering.

Quailbush (Atriplex lentiformis): This native shrub has small grayish leaves and grows quite quickly and densely. As you might guess, it is a great attractant for our desert quail as well as other birds. It needs a fair amount of space — it can grow up to 10 feet tall and wide.

Mexican bird of paradise (Caesalpinia mexicana or Erythrostemon mexicanus): These small trees are one of my favorite plants. They have beautiful deep green foliage and spectacular, tropical yellow flowers that attract all sorts of pollinators, from butterflies to hummingbirds. It’s a near-native from Mexico and hardy to 15 F. It can grow in tree-shape or shrub shape, depending on how you prune it. It can get 15 feet high, but doesn’t take up much space at ground level. It likes a bit of supplemental water.

Bush dalea (Dalea pulchra): This native plant has lovely, airy light gray-green leaves and deep purple flowers that bees love. It usually grows about 5 feet tall and wide, but can grow up to 8 feet high. Once established it will not need additional water.

Evergreen sumac (Rhus virens var. virens): This shrub can grow 10 to 15 feet tall and nearly as wide; it’s native to Arizona, New Mexico, Texas and Mexico. It naturally grows on rocky hillsides, so it can adapt to any well-draining soil. It also likes full sun, but can tolerate part shade. It’s a great wildlife plant, attracting birds and small mammals with its fruit and pollinators with its flowers.

Slower growers

Arizona rosewood (Vauquelinia californica): This beautiful native will grow to nearly 30 feet if given time. It’s a great alternative to oleander; it’s leaves and flowers are similar in form but it’s a native that’s very wildlife-friendly and is non-poisonous. More frequent regular irrigation will speed up its growth. It likes full sun, and is thornless.

Desert lavender (Hyptis or Condea emoryi): This native can be somewhat less dense, particularly if it’s planted in shade and gets leggy. It’s greyish foliage has a pleasant scent when you brush against it and is thornless, so it’s a good candidate for areas where people walk or congregate. It’s also a great habitat and food plant for native pollinators thanks to its lovely purple flowers. It can grow up to about 8 feet tall.

Jojoba (Simmondsia chinensis): A thornless, native shrub, the jojoba has beautiful oval grey-green leaves and produces nuts that we harvest for their oil. It can suffer some foliar damage in temperatures below 20 F, but the roots will usually survive (particularly in established plants). It grows into a very thick hedge up to 8 feet tall and wide.

Little leaf ash (Fraxinus greggii): This large shrub can also be grown as a small tree with appropriate pruning. As with many native slow-growers, it will grow faster with additional regular irrigation. It is thornless and has bright green leaves with grey attractive bark. It can grow up to 20 feet tall and about 10-15 feet wide.

Sugar bush (Rhus ovata): This long-lived native shrub can be grown into a small tree as well. Plants can live up to 100 years. It has lovely shiny dark green foliage and starts producing flowers after four to five years. It will grow faster in less extreme conditions, such as regular irrigation and part sun. The fruit is edible, and will attract wildlife, while the flowers are great for pollinators. It can get to 15 feet tall and wide.

Gray thorn (Ziziphus obtusifolia): As the name implies, this one is very poky, which may be an asset if you’re trying to keep people or larger animals (like deer and javelina) out of your yard. It’s native to the desert southwest. A great plant for birds and small mammals due to its dark blue berries, which are also edible to humans.

The best way to plant a tree in Tucson

How do you plant a tree? As the old joke goes, green end up. In Tucson, it’s a bit more complicated, and one big reason for that is caliche.

Caliche is a hardened soil layer common to desert soils. It is made up of calcium salts and minerals (mostly calcium carbonate) which are naturally present in the soil. In rainier places, minerals and salts in the soil are flushed through by rainfall. In drier climates like ours, over time these salts and minerals build up and form a hard layer (also called hardpan) anywhere from several inches to several feet thick.

Anyone who’s tried to dig a hole by hand in Tucson knows what it’s like to try to dig through caliche — a pick or a caliche bar will be your best friend. For larger jobs, you may need to rent a jackhammer, or even a backhoe. It can help to soak the area before you dig; that can make breaking up the caliche a bit easier.

This hard layer makes it tough on new plants — particularly trees — because their roots won’t get the drainage or the room they need if you leave the caliche in place. In addition, if a tree’s roots end up growing shallow due to the caliche layer, the tree will be in danger of toppling once it gets taller. This would not only kill the tree, but potentially be a hazard to property and people. The University of Arizona Extension Office has a helpful handout on managing caliche.

Guidelines for tree and site selection in the Sonoran desert

• Select a native or desert-adapted tree. These trees will be more adapted to our desert soils and will cost you less in watering and maintenance. You will also want to select a healthy tree from the nursery; here are some guidelines on what to look for.  If you want a mesquite or palo verde, check out this helpful guide from the University of Arizona.

• Select a good site for your tree. Avoid areas where it will cause a potential hazard, such as near power lines, near property lines, or close to your plumbing or septic system. This handout from the University of Arizona’s Extension office has some great tips, along with great examples of what not to do.

• Plant the water before you plant the tree. The Watershed Management Group has a great handout to help you ensure that your new tree has all the water it needs throughout its long life. After the initial two- to three-year establishment period, native trees can thrive on rainwater only.

Steps to planting a tree in the Tucson desert

There are steps you can take during planting to help ensure that your tree is an asset to your property and has healthy roots:

• Dig a hole that is slightly less deep than the container the tree is in, and three to five times as wide.
• To test drainage, fill the hole you just dug with water, let it drain, then fill and let it drain again. If the water takes longer than 24 hours to drain the second time, this could be due to caliche. Look for a caliche layer while digging; if you find it, you need to do one of two things:
  • Dig out the caliche layer throughout the entire planting hole and discard the caliche fragments. This is a lot of work if done by hand, but if you have machinery — jackhammers or backhoes — it can go more quickly and will be worth it in the long run.
  • Dig out a couple of drainage chimneys through the caliche layer next to the root ball (not under it) to help with drainage; fill these drainage holes with the same native soil you use for planting your tree.
• Remove any burlap or wires gently from around the root ball.
• When you put your tree in the hole, make sure the very top of the root ball is slightly above the grade of the rest of the hole. This is because you do not want any of the tree’s bark to be under the soil or the mulch layer.
• Back fill the hole with native soil; avoid using soil amendments with the exception of mulch or compost.
• Create a berm around the tree to hold water and allow it to infiltrate when you water your tree.
• Remove nursery stakes. These are unnecessary and are inadequate if the tree truly needs staking; use tree stakes and ties specifically for that purpose.
• Water your tree to a depth of 3 feet and then mulch with at least 2 to 3 inches of mulch. Keep the mulch a few inches away from the trunk to prevent rot.

Even native trees will need to be watered regularly for the first couple of years until they become established. Always water your tree out at the dripline (not at the trunk) to a depth of 3 feet to encourage wide and deep root growth. Use a soil probe to check how deep your watering is; this is just a pointed iron bar with a handle on one end. It’s much better to water a tree less frequently and deeply than to give it daily shallow waterings. Drip systems are best for these types of watering, but keep in mind that you will need to move the drip line and emitters outwards as the tree grows so you continue to water it at the dripline.

Where to find native trees in Tucson

Tucson Clean and Beautiful has a website called Trees for Tucson where you can order 3-foot tall trees for $25-$30. Not all the trees are native. If you’re a Trico Electric customer, you can get a discount on the Trees for Tucson site. If you are a Tucson Electric Power customer, you can participate in their Trees for You program and get discounted trees from local nurseries.

Other places to get native trees in Tucson include:

• Desert Survivors
• Spadefoot Nursery
• Civano Nursery
• Harlow Gardens
• Tohono Chul Retail Greenhouse
• Green Things Nursery

For more detailed information, check out these other resources:

• Planting Guidelines: Container Trees and Shrubs
• Choosing the best orange tree for your Tucson yard from the University of Arizona Extension office
• Arizona Tree Planting Guide
• Arizona Department of Forestry and Fire Management: Tree Selection and Care
• Arbor Day Foundation: How to plant your trees
• Watering Trees and Shrubs
• Landscape watering interactive guide

7 tall trees for the Tucson landscape

A lot of our native trees are on the small size. This works very well for small backyards and patios, but sometimes you just need a tall tree to provide lots of shade and to draw your eye upward to the sky.

Tall trees are also great habitat for owls, bats, and other flying predators. Because of their size, however, you want to pick a tree that won’t need huge amounts of water during its long life.

I’ve put together a list of some tall native trees that you can consider in your landscape. Be sure to read more about them if you decide to plant them. Most of these trees are from our riparian zones, and thus will do best in a wetter, shadier area, for instance near a stream bed. If you don’t have the fortune of your own stream bed, you can create one in your yard to capture rainwater or gray water, and improve the conditions for these trees without having to water them constantly.

Some of these trees will be hard to find at regular nurseries. Check out Spadefoot Nursery and Desert Survivors Nursery to see if they have them or can procure them for you.

Honey mesquite (Prosopis glandulosa var. torreyana): This tree is native to our area, and usually grows to about 30 feet in the wild, but it can get as high as 60 feet. It’s extremely hardy (to -30 F) and can grow in full sun. If you want it to get taller, you will need to give it regular water, unless its roots can reach the water table (like near a stream). This is a wonderful tree for wildlife.

Canyon hackberry (Celtis reticulata):  This is a great native habitat tree but will need to be away from walkways and buildings due to its thorny branches. It grows to 50 feet, needs a bit more water than mesquites and palo verde trees as it’s native to our canyons and riparian areas. It will survive on low water, but it won’t look its best. It’s very thorny and rather scraggly-looking when young, but will eventually grow into its shape; hardy to -20 F.

Texas ebony (Ebenopsis ebano): This near-native tree can grow as high as 40 feet, but it will take a long time to get there. It’s also quite thorny, and produces large brown pods, so it’s not a good tree to put in patios, walkways, driveways, and the like, but it’s great for low-traffic areas. It’s evergreen in Tucson, and hardy to 10-20 F (sources differ). It’s beautiful dark green foliage, creamy flowers, and great bird habitat makes up for its downsides.

Utah juniper (Juniperus osteosperma): This near native is a good evergreen tree for our area, since most of the native junipers and cypresses tend to grow above 3,500 feet. The Utah juniper is happy in the low desert, but prefers afternoon shade. It grows up to 40 feet tall, is drought tolerant and hardy to -25 F. Many conifers have been doing poorly in Arizona due to climate change, so make sure you put this in a spot where it won’t get too heat-stressed.

Mexican blue oak (Quercus oblongifolia): Most of our native oaks do best at higher elevations, but this one should be OK at our elevation as long as it has some afternoon sun. It grows to about 30 feet, so it’s one of the shorter trees on this list, but oaks are important habitat and food trees for wildlife so I wanted to include one. It will need some supplemental water, but not a lot. It’s very hardy, to 0 F.

Velvet ash (Fraxinus velutina): This native tree tends to grow in riparian zones, so it will do best with part shade and more water than other native trees. It grows to 40 feet, and is hardy to -10 F. It’s a great habitat tree for birds, butterflies, and other wildlife. It is deciduous and turns a lovely yellow color in the fall. This tree will do best at elevations near and over 3,000 feet.

Arizona sycamore (Platanus wrightii): This native can grow up to 80 feet tall and is hardy to -8 F. It’s deciduous and has beautiful fall color. It will require regular water, however, since it’s used to stream beds, so consider watering it with gray water so it gets a steady supply.

More resources:

• Spadefoot Nursery’s tree selection guide 
• AMWUA tree guide
• University of Arizona Campus Arboretum 

Which trees and shrubs to plant for a lush green desert yard

Your Tucson yard can have that lush green look you see in gardens in other climates if you choose your plants carefully — there are many drought-tolerant plants (even some natives) that will give you rich green foliage and tropical-looking colorful flowers. 

Keep in mind that you will need to water these plants more often and also note that the hardiness temperatures generally indicate the temperature at which damage occurs to the foliage. It is rare for the plants listed below to die completely (to the roots) in our climate if they are healthy and well-mulched and watered. If some branches and foliage are damaged, they can be pruned back in the spring and generally recover quickly.

Lush trees for Tucson gardens

Anacacho orchid tree (Bauhinia lunarioides): This beautiful tree is native to the Chihuahuan desert and has lovely large white orchid-like flowers. It’s hardy to 15 Fahrenheit and can grow in full or partial sun (which in my experience usually means that harsh afternoon sun should be avoided). Do not plant where it will be subjected to reflected heat. It grows at a moderate rate to a small tree (about 8 feet high) and is shrubby in form.

Desert willow (Chilopsis linearis):  This fast grower is native, and can take our full sun and even reflected heat. The leaves are a lush green, and it has gorgeous orchid-like flowers in a variety of colors from white to pink to purple (depending on the cultivar). It’s hardy down to 0 Fahrenheit, and birds and hummingbirds love it.

Feather bush (Lysiloma watsonii):  This lovely small tree grows to 15 feet in height. It’s native to our desert and has beautiful lush green tiny leaves that give it a feathery appearance. Its flowers are cream-colored puffy balls that bloom in late spring. It’s only hardy to 25 Fahrenheit, so make sure you put it in a warm spot in your yard.

Texas ebony (Ebenopsis ebano): This Texas native is a slow grower and has thorns, but it has beautiful lush dark green leaves and creamy yellow flowers. It’s hardy to 20 F and can take full sun.

Mexican Bird of Paradise (Erythrostemon mexicanus): This beautiful little tree can be considered a shrub; it has deep green oval leaves and warm yellow flowers that grow in clusters. It’s hardy to 15 F and does well in the sun, although in my experience it likes partial shade better. It gives lovely filtered shade thanks to its small leaves.

Silk floss tree (Ceiba speciosa): This tropical tree is native to Brazil and Argentina. As such, it requires more water than the other trees mentioned, but its unique, thorned trunk and spectacular fall flower show make it worthwhile. The flowers are similar to hibiscus, pink in color, and are 5 inches in diameter. The tree is hardy to 26 F and will tolerate drought and full sun, but will look better when watered regularly. It will need to be protected from frost when it’s small, and should be planted in a warmer area of your yard. It grows to 20-30 feet, so be sure you have lots of room for it! These can be hard to find, but Plants for the Southwest has them.

Pomegranate (Punica granatum): This mediterranean plant not only has glossy dark green leaves and unusual orange flowers, it also produces edible fruit. It’s hardy to 10 F but needs a bit more water than our natives to keep it from looking scraggly. It is deciduous, and loses all its leaves in the winter.

Lush shrubs for Tucson gardens

Arizona yellow bells (Tecoma stans): Bright yellow trumpet flowers and rich green foliage make this native a great addition to your yard. Hummingbirds love the flowers. It’s a little frost sensitive (hardy to 25 F) but will grow back if damaged. It’s a fast grower and likes full sun. There is also a variety called Orange Bells which is less cold-hardy.

Hopseed bush (Dodonaea viscosa): This native fast-growing bright green shrub is a great choice for an informal privacy hedge. It has a fresh green color, and female shrubs have pretty light green seed pods. Birds love these. It can handle full sun and is hardy to 15 F.

Mexican petunia (Ruellia brittoniana; Ruellia simplex):  This small shrub has dark purple flowers and medium-green leaves. It’s native to Mexico and the Southwest U.S. It’s hardy to about 28 F and will need a warm spot. It will need regular watering to look its best, particularly in summer. You can find white and pink varieties in addition to the deep purple.

Guayacan (Guaiacum coulteri): This 5-foot shrub grows very slowly, but has striking violet flowers and deep green leaves. It’s hardy to 25 F and does best in partial sun.

San Marcos hibiscus (Gossypium harknessii): Believe it or not, this is a native plant. It has light yellow flowers with red accents, and deep green leaves. It’s hardy to 25 F and doesn’t mind full sun. It can be hard to find, but Spadefoot Nursery has them from time to time, and can obtain them if requested.

Texas mountain laurel (Dermatophyllum secundiflorum): This Chihuahuan desert native is hardy to 5 F and has beautiful rounded dark green leaves. It is known for its clusters of violet, fruity-smelling flowers. It is a very slow grower, so tends to be expensive if bought in a larger size. Eventually it grows into an 8 foot shrub.

Texas olive (Cordia boissieri): This Texas and Mexico native doesn’t have the dark, lush green foliage (it’s grayish-green), but I included it because of its beautiful and plentiful white orchid-like flowers. It’s hardy to 20 F. It will require patience, as it’s a very slow grower.

Cape Plumbago (Plumbago auriculata): This plant gets a bad rap for using too much water, but if planted in the shade and mulched it’s just as drought-tolerant as many of our natives. It has deep green foliage and attractive clusters of small tubular blue-violet flowers. There are also white varieties. I have it growing in shade on the eastern side of my house and I don’t water it any more frequently than the desert willow tree next to it. It needs a fair bit of room, as it tends to sprawl, but this can be an advantage if you want to attach it to a trellis for privacy.

Bougainvillea (Bougainvillea spectabilis): Despite its large thorns, this Brazil native is a good choice for a lush garden due to its gorgeous colors and lush dark green foliage. The color actually comes from the bracts; the flowers are tiny, white and unassuming. It gives you vivid tropical colors and is safe to plant in dry, sunny exposures. There are many Bougainvillea varieties to choose from. Certain smaller varieties do well in containers. Colors run the gamut: white, yellow, apricot, hot pink, and purple. They can sprawl, but you can purchase smaller varieties. Larger varieties can be trained on a trellis and provide a backsplash of color to your garden wall. A dwarf variety called "Miss Alice" is thornless and can be grown as a groundcover of sorts. Bougainvilleas are happiest when allowed to dry out between watering, so be careful not to overwater them.