Arizona Rosewood Is True Desert Native and Does Not Require Frequent Watering

Q. We have an Arizona Rosewood tree in our back yard. It is about 8 years old, is a double trunk tree with 4 inch circumferences on each trunk.  It stands about 12 feet tall and is about 12 to 15 feet across. One water line presently waters it 3 times a day for a total of 30 minutes and is about 15 inches from the trunks. It has been fertilized with Miracle Grow tree and shrub fertilizer

and has been treated for possible infestation of insects or grubs. 

     We have noticed that some of the leaves have been turning brown and falling from the tree. 

     Can you give some info on how many water lines it should have, what their locations should be and about how much water the tree should receive or what other problems we may be able to look for? 

A. This is the wrong irrigation schedule for Arizona Rosewood. This plant originates from the Sonoran Desert so it is a true desert plant. This means that it doesn't like frequent amounts of water in small amounts as you are giving it.

            Normal for it would be watering not very often in the winter but giving it large amounts when you do and the same amount but more often in the summer. Yes, this is a bit vague but the watering schedule you have for it now is for nondesert plants.

            With this type of schedule it is possible that it is getting water too often. It is also possible it is not getting enough water when you do water. Hard to say.

            The problem now is that this tree is accustomed to frequent watering with small amounts. Its roots have grown to favor this method of watering. At this age, this tree may have some difficulty adjusting to a new watering schedule.

            One thing we can conclude is that it is a watering problem; either too often or not enough when you do water. It is definitely not a problem of watering too often AND too much combined. If you have never added drip emitters around this tree it may be time to do so.

            I am GUESSING it is not getting enough water when you are watering. Increase the amount of water by adding more drip emitters. This is better than increasing the minutes. If you increase the minutes then EVERYTHING on that cycle will get more water, whether they need it or not and it will waste water.

            It is less likely, but possible, that the roots of the tree are getting water too often. This can cause the roots to rot particularly for many desert plants.

            If I were there I would go out to Home Depot or Lowes and get an inexpensive moisture meter for houseplants. Bring it home and push it into the soil in several locations around the tree. Use this for deciding if the plant is getting enough water or not. 

Inexpensive houseplant moisture meter that you can use outside as well to see if the soil is moist or dry before watering.

I posted this information sheet from Andrea Meckley previously.