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A Newsletter of the Tatum Highlands Community Association

August 2023

By Ed Sieckert, MS
Certified Professional Agronomist

So you have decided to plant a new tree in your landscape! There are a number of choices. You can view them in Landscape Plants for the Arizona Desert at Visit a good nursery in the Phoenix area and talk to their tree specialist who can help you with your selection.

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I am going to use one tree species for this example: the Palo Verde Desert Museum variety, multi-trunk, which is the State Tree of Arizona. It was developed by Dr. Mark Dimmit of the Sonora Desert Museum in Tucson. A unique feature is that it has no thorns or pods, making it very suitable for the landscape. An abundance of yellow flowers appears each May which will reward you with so much yellow color it will enhance your yard.

Multi-trunk: Why should I buy a multi trunk tree and continue to prune and train it? Desert native trees normally have lower limbs close to the soil to help retain moisture. In the landscape, we must consider the health of the tree and its limbs. A multi branched tree will allow air to move through and around the limbs. A single trunk with a tall set of limbs is easily windblown and results in limb fall.

Selecting your Tree: Purchase a tree in a 24-inch container or box and have it delivered to your home and they will plant it for you. The best time of year to plant is September/October to let roots develop in cooler weather prior to winter. An alternate planting time is March.

Planting is the most critical step in the life of the tree.

Step 1: Digging the hole

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The hole should be 4 inches deeper than the container root ball. The width of the hole should be 3 to 5 times the width of the root ball to give the new roots a chance to venture and provide a strong root support for the tree when the winds come later in its development.

Step 2: Watering the planting hole

Fill the hole with water to the top of the soil line. This allows 3 things: (1) Hydrates the soil and helps the root ball interface with its new home; (2) Helps settle the soil giving a firm foundation to the root ball; (3) Helps you see how fast the water penetrates the soil and provides you a drip emitter selection. Let it soak into the bottom.

Step 3: The Container

Lay the container on its side and cut the bottom of the container off. Remove with a saw ½ inch of the root ball. Carefully slide the root ball into the hole. Remove the plastic from the side of the container. Backfill with original soil, tamping it with the
shovel handle to remove air pockets. Continue to fill the hole to the top of the root ball.
Note: Planting mixes are not recommended for mixing with the original soil.

Step 4 Placing a berm around the tree

Place a raised berm circle around the tree. It should be at least 4 feet in diameter. Then apply water to make sure the roots are settled in and help start the new tree off with good irrigation. Remove the berm after 1 week.

Step 5: Installing the drip tube emitters

You want the roots to grow outwards from the root ball to support the trunk and branches of the tree as it develops. Placing an emitter on either side of the tree trunk will NOT help the tree in later years and will result in tree imbalance and loss of limbs.

Install an initial set of 2 emitters, each 18” inches from the trunk to help it get started. The next set of emitters is arranged in a concentric circle at 3 feet from the trunk. The next set is 6 feet from the trunk. The next and final set is at 9 feet. See example (Fig 14) for the number of emitters. All of the emitters are placed at the same time.

The Palo Verde tree grows quickly and within 2 years the canopy width will be 9 feet in diameter. That is why we place the emitters out to 9 feet at date of planting. Roots develop out to the 9-foot diameter where the emitters are placed.

If you follow this setup, you will have a good root system to withstand the strong winds we see in this valley and minimize limb loss in future years.

Irrigating the tree is important for good development.

Note: For how much water to apply and irrigation timing, see the article
Watering Your Trees and Shrubs reported in the May 2023 issue of The Highlander, the Tatum Highlands newsletter.

Appreciation is expressed to Arid Zone Trees of Mesa, Arizona, the University of Arizona and the Arizona Municipal Water Users Association for the recommendations for planting and irrigation. Arid Zone Trees website has excellent reference material and photos of tree planting, irrigation, tree selection and management over the years. The University of Arizona has a great Master Gardener website to help homeowners with diagnostics of problem plants as well as help on specific shrubs and trees.

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