Irrigation for Desert Adapted Trees

Typical Irrigation Schematic

Improper irrigation of desert adapted trees can cause their premature death! 

On the diagram above I had tried to draw out how we would recommend that you drip irrigate a large desert adapted tree, if it needs water at all. In a landscape where there are flowers and bushes, desert adapted trees may not need any supplemental water. By observing the tree you can tell if it needs more or less water!

If the tree is growing more than about 12-18″ per year, chances are it is getting too much water! Most are! In this case, cut off the water to the tree! Your tree will grow more manageably and require less trimming.

If your desert adapted tree starts to lose leaves during the hot part of the summer (before the summer rains) chances are it needs more water! You can just lay out a hose and let it run for a day or so out under the canopy (in several places). You might only need to do this once or twice a year! It depends on your soil and the other things in your yard that are getting water near the tree. Mesquite trees will send roots out quite a ways for water, so it doesn’t necessarily need to be other things near the tree!

If you want to put drip irrigation on your trees, make sure the trees are on a separate valve from the bushes and flowers. The trees need water less frequently and longer than the small plants. If you have everything mixed together, it will be hard to make it work! With separate valves, you can just run your tree line manually for 12-24 hours a couple times in the hottest part of the year and the trees will be fine!

One thing we are trying to do with this setup is keep the trunk of the tree dry. We want the soil around the base of the trunk and the main anchoring roots to get dry and hard! There are no absorbing roots there anyway! If this soil is hard, the roots will hold the tree up! If the soil here is mud, the anchoring roots can’t do their job and the tree may topple! See this article for more information on this.

The picture below shows a really nice Bowsmith emitter set up to go on poly line. They work with PVC too. Six adapters plug into the red part and 1/4″ drip lines plug into them. This emitter is designed to be self-cleaning and can be buried under the ground with no problem. We use one of them on a new tree (two on an established tree) with 5 of the drip tubes running out under the canopy like we show in the drawing above. The 6th drip tube goes over to the original root ball on a new tree and is left there for 30-90 days at which time it can be capped or moved out under the canopy with the rest of the emitters. This ensures that the root ball of the new tree stays moist while the roots are exploring the native soil around the planting hole and getting established.

6-way Bowsmith emitter set up for installation on poly tubing

Proper irrigation of native desert-adapted trees is not rocket science – why can’t they get it right?