Growing Avocados In Phoenix Arizona

Photo
The avocado tree pictured on the right was planted 14 months ago in July. It is planted on the west side of a wall and the east side of a peach tree. The peach tree almost overhangs the avocado, so it gets a fair amount of afternoon shade.

During the last two summers, a shade cloth has been placed on a structure above it. This avocado tree is a variety named Zutano, which is Mexican in origin. A Haas avocado tree was attempted in this same location and died in the middle of summer, even though it was in full shade. The Haas shriveled up like a piece of lettuce in the sun when temperatures went over 115 degrees Fahrenheit.

Winter temperatures as low as 26 F., did not affect this tree. However, a ring of salt from the neighbors flooding their vegetable garden, on the other side of the wall, came very close to killing it. They use manure in their garden which tends to make the soil salty. My usual cure, gypsum, seemed to make things worse in this instance, but the tree is still hanging in there.

Overview
Avocado trees seem to be the gardening urban legend of

Phoenix. Supposedly there are large mature avocados somewhere in the Phoenix area, producing bushels of fruit, and when the moon is full there are fairies and leprechauns playing in the branches. Okay, I made that last part up, but I have yet to see a large avocado tree growing in the ground here. The above picture does show that they can be kept alive with a fair amount of pampering but the jury is still out as to whether this tree will at some point start to take off and size up. The main problems with growing avocados in Phoenix is that they don't like the summer heat or the salty soil and water. Winter cold does not seem to be a problem with the more hardy varieties.

Heat Tolerance and Sun Exposure
Young avocado trees definitely need afternoon shade in the lower Sonoran Desert and should be shielded from the sun with shade cloth in June, July, and August. Being on the east side of a deciduous tree is an ideal spot because the tree will get the protection it needs in the summer, but will get full sun in the winter. As for heat tolerance by variety, I have found that Haas avocado trees cannot take the summer heat here no matter how much shade they get while Zutano avocado trees can.

Cold Tolerance
The more cold tolerant Mexican avocado varieties are able to take temperatures as low as citrus trees can. So, there is not much reason to be concerned about them in developed areas of town. My Zutano tree survived temperatures as low as 26 F. without a single damaged leaf, while many of the ficus trees in the neighborhood were killed.

Planting
Dig a hole at least twice the size of the rootball. At a minimum, make the hole 2 feet in diameter and 1 foot deep. Work in a 50/50 mix of compost to soil. Be sure to mix the compost and soil as thoroughly as possible. It also is a good idea to finish with the hole an inch or two recessed so that a watering basin is formed.

Watering method
The biggest challenge for growing an avocado tree here is the salinity of the soil and water. Basin irrigation is the most effective watering method for pushing salt away from the trees root ball.

Watering frequency
Avocado trees do well on a grass watering schedule. An occasional deep soak is beneficial if the trees leaves are showing signs of salt burn. Deep soaking is done by turning the house on very low and letting it run at the base of the tree for several hours. Deep soaking will help to wash salt to the edges of the area of soaked soil. After deep soaking, one can often see a visible ring of salt.

Fertilizing and Growth Rate
Fertilizer can raise the salinity level of the soil, so chemical fertilizers should be avoided if used at all. So far I have only used compost but I might experiment with some fish meal.

Pests
Avocados have no significant pest problems in Arizona.

Links to more avocado information

Growing avocados at TAMU Growing avocados at CRFG Avocados at Wikipedia