July 1, 2017
1 - Desert willows often start life as shrubs and become multi-trunked small trees or large shrubs, so breakage is not a major problem for them.
Yard and Garden July 1, 2017
We have a small Desert Willow whose main trunk broke at about the 2 foot mark and now it is sending out horizontal branches (4 or 5) that are about 5 foot long and sprawling. Branches are an inch or so in diameter. I know, Johnny come lately to questions about what to do. I realize we could try propagating another tree from a cutting. Do you have any suggestions? A bush is fine, I am not trying to prune it for a tree….which is not possible given where it broke.
In nature the desert willow often begins life as a shrubby plant with numerous low branches. Over time one, or usually more, branches become dominant and become “leaders” or trunks. The result is a multi-trunked small tree or large shrub. We often prune the desert willow to a tree-like form with a single trunk, but that is not necessary. Some people prefer the multi-trunk appearance that is natural for this plant.
You now have a plant that is growing in the more natural form. Breakage is common in nature, so your plant is doing what is natural for this species. It will produce a shrub form that may develop the multi-trunk appearance over time. Since you said that a bush (shrub) form of growth is acceptable, then you really do not need to train the plant. Over time as it develops multiple leaders, you may want to prune weaker growths back and perhaps you will choose to trim away lower branches, but this is not necessary unless your situation requires no low branches.
It would not be impossible to try to train it to tree form by selecting one branch in a proper location (lowest on the old trunk or from underground). If it is growing horizontally you may use a stake to train the selected branch to grow upright. Other branches will help provide nutrition to the root system, so you may choose to retain the additional branches for a few years. You can prune them back to subordinate them and further favor the single trunk form, but by not removing them completely they can help to support the root system which will support the newly forming trunk.
You may also choose to favor the more rapid development of a multi-trunk form by selecting several branches to train upright as leaders. This may happen naturally over time, but you can encourage it by removing surplus branches and training a few leaders.
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Curtis W. Smith, Ph.D., is an Extension Horticulture Specialist, retired from New Mexico State University's Cooperative Extension Service. NMSU and the U.S. Department of Agriculture cooperating.