Are Bottle Trees Really Desert Trees?

Q. Ten bottle trees planted last year thrived but then suddenly lost all their leaves at the very top during the wind. The trees are watered with drip twice a day, three times a week for the past month. The rest of the trees and the leaves look healthy. My landscaper suggested that the wind stripped the leaves. I have doubts since my neighbors' bottle trees of the same age look perfectly healthy.

Bottle trees do well in Las Vegas but are very large and not true desert (xeric) trees. These trees originate near waterways in Australia. And at 60 foot heights there is no way it can be called ":Low water use". Maybe for a tree that is 60 feet tall it can be called "low in its water use" but it is not a low water use tree.

A. I like to follow the KISS principles and get these possibilities out of the way before I jump to unusual solutions like strong wind. I suspect this problem may be associated with their watering and not necessarily the wind. Trees may lose their leaves at the top either from lack of water or watering too much. Both cause leaves to loosen from the branches and the wind just blows them way. By the way, a quick google tells me bottle trees get 60 feet tall with irrigation; big trees as they get older.

Many bottle trees are used in lawns. They are mesic so that should give them enough water provided the soil drains water.

            Irrigations applied two or three times per week in late April and early May would be about right for established trees provided they are given enough and it is applied to a large area under the canopy. This means the amount of water should not be measured in minutes but in gallons. The number of emitters and their spacing is important information to tell me because these are responsible the amount they apply and for distributing the water under the tree canopy.

As long as it is surrounded with other mesic plant getting water it is fine in a desert (rock) landscape.

            Trees planted from 15-gallon containers should get at least 8 to 10 gallons of water when first irrigated and probably double that the second or third year as the roots explore the surrounding soil and the tree gets larger and more established. Two or three drip emitters placed 12 inches from the trunk are all that is necessary the first year after planting.

As long as bottle trees get enough water and it is applied deep enough and not too often, they will grow well. The biggest problem is not getting enough water when it is watered.

But by the second or third year after planting, the trees need more drip emitters further from the trunk. Doubling the number of emitters and placing them further away from the trunk accomplishes this without changing the number of minutes.

When bottle trees are surrounded by rock, or at least on one side, they may not get enough water.

With a thin piece of 4-foot long rebar, make sure the water is applied deep enough by pushing it into the soil in several places immediately after an irrigation. The soil around bottle trees when young should be wet to about 24 inches deep immediately after an irrigation and 36 inches deep when they get bigger.