Tricks of the Trade for Healthy, Shady Trees
By Eddie Rodieck
Perfect for climbing, tire swings and excellent shade, trees can add beauty and functionality to any yard. Although growing trees in the Sonoran Desert isn’t always easy, there are certain varieties that do very well in Southern Arizona. Here’s a few of the trees that can flourish in our desert climate and tips on how to care for them so they can provide years of abundant shade, pushing down electric bills and offering a cool place to relax outdoors even in our sizzling summer months.
The Chilean Mesquite
This tree is one that grows quickly and will provide you with ample shade. A heat-loving, drought tolerant tree, the Chilean Mesquite offers an airy, open crown with refined foliage and young stems that appear to be purple in color. The average Chilean Mesquite will grow to 30-feet tall at full maturity and requires only occasional watering once it has become established.
An excellent choice for planting in dry rock gardens and drought-resistant landscaping, the Chilean Mesquite is perfect to plant near patios and pathways for its abundance of light shade. When planted in groups, the canopy can filter the harsh rays of the summer sun to reduce cooling bills and offer a respite from the glare. Be sure not to plant this semi-evergreen too close to walls, foundations, patios, or sewer lines though as the roots grow large and will break up piping and concrete.
Desert Museum Palo Verde
A big, fast-growing tree, the Desert Museum Palo Verde will grow up to 25 foot in height at full maturity. It requires full sun, but is drought tolerant making it a perfect selection for the Sonoran landscape. Once established, it only requires occasional watering, yet offers terrific shade with very few seedpods.
The Desert Museum Palo Verde is a thornless hybrid that sports yellow blossoms in the spring adding a dash of terrific color to your yard. This gorgeous tree tends to last longer than others in its species and may even re-bloom in the summer if provided with supplemental water. Though the foliage may fall, the trunk and stems remain green throughout the year.
Heritage Live Oak
The Heritage Live Oak is a slow-growing tree that is medium in size with an average height of 25 foot when fully grown. This tree, related to the Southern Live Oak, has been adapted to the conditions of the desert and grows somewhat faster than its parent.
A Heritage Live Oak will do well in full or part sun and is considered a member of the evergreen family. This stunning tree offers a blossoming of yellow flowers in the sprint with green foliage throughout the year, but does require more water than the Chilean Mesquite or the Desert Museum Palo Verde. It does well in sand, clay, and loam soils that are well drained.
Another tree option for Southern Arizona is the Texas Ebony. A colorful, slow-growing, ornamental tree, the Texas Ebony works well in small places, tolerates wind and compacted soil well, and can grow in acidic, alkaline, sandy, or clay soils. While it requires care and watering when young, this tree is capable of surviving the driest conditions when it is established.
Perfect as a street tree or shade tree, the Texas Ebony produced fragrant, creamy white and yellow flowers in the spring and even intermittently throughout the summer with added water. It offers dark green leaves that stay green throughout the year. The average Texas Ebony will grow to a height of 35-80 foot tall with a canopy spread of 20-30 foot at full maturity.
The Crapemyrtle is a small, deciduous shrub that will also do well in the desert conditions of Tucson and Southern Arizona as it is somewhat drought tolerant. This tree is capable of growing in a wide range of soil types from acidic to slightly alkaline and does best in moist, well-drained areas. The Crapemyrtle loves full sunlight and grows quickly.
Growing to a mature size of 15-25 foot tall, the Crapemyrtle is well-known for its profusion of striking, pink flowers. The shrub, which can also be grown as a tree, offers handsome bark and attractive foliage that can be planted in groupings to create hedges or screens. A favorite for colorful landscaping often called the “lilac of the South,” the Crapemyrtle can be planted directly into the ground or grown in large containers.
Like the Crapemyrtle, the Oleander can be planted as a shrub or small tree. It is an attractive option for warm climates such as the Sonoran Desert and produces heavily scented, colorful flowers ranging from white to red and yellow through the summer and fall. Growing best in the full sun to lightly shaded areas, the Oleander is poisonous to humans and animals alike if ingested so may not be the best to plant if you have children or pets. Additionally, the sap of the plant may cay skin irritation in some people.
The Oleander is well adapted to warm, dry climates and can withstand dry conditions as well as wind. These shrubs can grow between 6-12 feet tall and wide and can be trained to grow into trees as tall at 20 feet high. Cherry Landscape recommends applying compost under the plant each spring, spreading it out to the dripline. In addition, a layer of mulch two inches thick will help the Oleander retain moisture and discourage weeds. Oleanders can be pruned after the main bloom period to allow for bushier growth and encourage the blooming of more flowers.
Southern Arizona Ash
A large, deciduous shade tree perfect for shade and along the street, the Southern Arizona Ash requires more water than the other trees aforementioned. It makes a glorious addition to any yard in need of thick, cool shade and is perfect for the desert. The Southern Arizona Ash does lose its leaves in the fall, so this tree does require some extra maintenance. There are male and female flowers on different trees that provide a continuous source of seedlings for this fast-growing tree.
A native to Arizona and other parts of the Southwest, the young trees are shaped like small pyramids, but fill out into a more round shape as they mature. Hearty in hot, dry, alkaline soil, these trees have a gray bark and a velvety soft gray fuzz covering its young twigs and leaves. This tree does best in the full sun and grows up to 30 feet tall.
While Sycamore trees require an abundance of water in a moist, well-drained soil, they make incredibly handsome shade trees for larger landscapes. These large deciduous trees can grow 75-100 feet tall with a similar canopy spread. The trunks of these trees can grow to as much as 10 feet in diameter and the root system can be quite damaging to concrete if planted near sidewalks and patios, so be sure to give these trees plenty of room to grow.
Sycamore trees are best recognized for their colorful bark pattern which offers a gray to brown outer bark that peels off in patches to reveal a light gray or white wood beneath. Older, more mature Sycamore trees often have solid, light gray trunks. These trees have 1-inch balls that hang down during the winter months and drop in the spring, producing a lot of litter that requires cleanup. Care for this tree is simple, but these trees should be fertilized every other year if they aren’t growing fast enough or if the leaves are pale. Young sycamore trees should be watered deeply and, after the first couple of years, more mature trees are able to resist conditions of moderate drought.
Elm Trees are another deciduous tree that will do well in the desert, but requires a lot of water. Known for their oval-shaped leaves with serrated edges, the Elm produces ample shade and bark that has rough, deep grooves. These trees offer terrific shade as a street tree or in a yard with their umbrella-like structure and wide spread limbs.
Elm trees flower each spring and then drop round, flat seeks with little hooks later on so require some clean up. These trees, which have dark green leaves, do great in the full or partial sun with moist soil. The size of an Elm depends on the species and a healthy Elm can survive for 200-300 years in the wild.
Considerations for Planting Trees
The placement of trees is very important to consider before planting begins. Before you select a tree for an open area, determine how much space you have. This will allow you to pick a tree that will best suit your space and purpose. Tree roots will extend as far as the canopy, which can cause damage to plumbing, irrigations systems, sidewalks, and patios if proper planning fails to occur prior to planting. In addition, the canopy itself will grow and can reach over homes and garages causing damage to window screens and roofing tiles.
Watering Your Trees
Once your trees are established, especially with Mesquite trees, it’s good to move the emitters away from the trunks. This forces the roots to reach further and grow deeper, preventing them from blowing over during monsoon season. Emitters should be capped off for desert trees if there is surrounding shrubbery as the roots will reach for water.
Pruning Your Trees
Generally speaking, trees shouldn’t be pruned within the first year unless they are impeding pedestrian traffic. By avoiding pruning in the first year, it allows your trees to become established.
Additionally, any wires and stakes used to hold trees upright and in place should be removed after the trees are mature and established to prevent girdling, the wire cutting into the tree bark. Don’t be fanatical about keeping your trees perfectly straight. Some of the most beautiful trees have the most character by growing sideways and then growing back upright. Trees are each different and unique, just like people.
Some Trees Never Grow
Some trees remain stagnant and unhealthy. If you are willing to take a chance and wait, the best thing to do is to cut them down to the ground and allow the tree to start over again. It doesn’t take as long as you think for this to occur. A 20-year-old tree will take only three years to grow back to its mature size because the root structure is already in place. Not only does the tree grow back healthier and stronger, this will allow you to prune and shape it in the direction you wish for it to grow to avoid making the same tree-growing mistakes of the past. As in nature, so it is in life.
If you should ever need help with tree selection, planting, or caring for your trees, know Cherry Landscape is always here to assist with your every need. Should you still have tree questions or need tree service, please contact your local tree experts at Cherry Landscaping at (520) 292-9776 or visit us online at www.cherrylandscape.com.