Issue: June 24, 2005

Eliminating ornamental pear fruits

Tree trunk split in the wind

We have a pear tree that bears fruit profusely, but the pears are not edible. We would like to prevent the tree from bearing fruit so we don't have to pick up pears every day and throw them away (and also so the ones that fall on the roof of our house do not begin to smell). Is there a way (perhaps a spray) that we can use to prevent the tree from bearing pears? We would prefer not to cut down the tree since it is a beautiful tree.

Small, inedible fruits are characteristic of many ornamental pears. Unlike the ornamental plum that can produce edible, very tasty fruit (when not prevented by frost), the ornamental pears are grown for their spring flowers. Their fruit is of no consequence but is often considered a nuisance.

The question you asked is a common question related to many trees that produce nuisance fruit. There is a product on the market, Florel Fruit Eliminator™, which may provide some reduction in the problem. This product contains a plant growth regulator called "ethephon" that releases ethylene gas. Ethylene has several effects on plants - one effect is to cause the young fruit to fall from the tree.

When using this product or any other chemical fruit thinning product, timing is important. To maximize its effectiveness, the material must be applied at the time recommended by the directions that come with the product. In addition to maximizing effectiveness, it is important to follow the directions to protect your health, the tree's health, and the environment.

At the Rio Grande Botanic Garden and the Denver Botanic Gardens a gardener can see plants from other regions (and from the Southwest) that grow and prosper in and northern New Mexico.

Our purple robe locust was split by the recent storms in the area and by wind gusts that came with them. We tied the tree together the best we could until we get some advice. The trunk is about 3" in diameter. Is it possible to save the tree (and for the tree to be healthy), or would we be better off taking it down and starting a new tree? If the tree can be bolted, please let us know your thoughts on that also.

You have a couple of choices in addition to replacing the tree. First, you can prune out the weaker of the two competing trunks. When two branches compete to be the trunk with a narrow angle between them, there is an increased chance that the trunk will split. Removing one of these competing trunks will result in a stronger tree. This can be done now. It will take a few years and perhaps some effort on your part to restore balance to the shape of the tree. Your tree is young and has a good chance to recover if a large portion of the top is removed when you do this.

Binding the trunk with material wrapped around it (as you have done) is good first aid. However, the binding material must not be left on the tree to cause girdling of the trunk. Bolting the tree by putting a threaded rod through the two competing trunks can help. Protect the tree with large washers against which the nuts will push as you tighten the bolt and draw the trunks together. Large washers will spread the force and minimize further damage to the trunks. In time, the trunks should graft together. You will then leave the bolt in place.

A caution: If someday you want use a chainsaw to remove the tree, remember the presence of the bolt, which may by that time be embedded in the trunk. It can be dangerous if the chainsaw strikes the bolt.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook.

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