Although most gardeners aim to bring in a good fruit crop on their plants, there are a few situations where a barren plant is preferred. Some homeowners would love to find a way to keep certain landscape plants from dropping their fruits onto driveways and sidewalks.
There are a few methods that can help reduce the amount of fruit production on both ornamental and fruit trees. Hand removal of faded blooms, or young fruits, works great for small plants but is not very practical for large trees or numerous shrubs.
Some plants can be sprayed with a solution to reduce the formation of fruits, but homeowners should be cautioned that the results are rarely 100 percent effective and not without risk of plant damage. Different plants will have varying degrees of success. Even different cultivars of the same species may react differently. And some of these products may actually promote fruit set, if applied at the wrong rate or time.
With these reservations in mind, there are a number of commercial products available if you want to give this method a try. A relatively new product on the market, Florel Fruit Eliminator, contains a not-so-new chemical called ethephon, which can reduce fruit set when properly applied. Other products include Naphthaleneacetic acid (NAA), which is often sold as Fruitone N or App-L-Set. Home growers may find this chemical difficult to find in small-sized packages.
Some variation in effectiveness may be due to the how the chemical is applied. The rate of application must be carefully adjusted. Too low of a concentration can actually increase the number of fruit that are set; too much can cause plant injury. Timing of the application is crucial to be sure fruiting is prevented. Depending on the specific product and plant combination, application may be recommended when flower buds are just beginning to open, during full-bloom or, in some cases, after blooms have faded and fruits are just beginning to set. Weather can also greatly influence the effectiveness of these sprays. Be sure to read and follow the label directions.
Of course, the best way to prevent unwanted fruiting is to select appropriate plant materials for your landscape. Where possible, choose a species of tree or shrub that does not have objectionable fruit. Some woody plants, including ginkgo, mulberry and ash, have male and female flowers on separate plants, and males will not bear fruit. Ask for named male or non-fruiting cultivars at the nursery, as this is the only way to be sure of the sex until flowering begins, which could be several years after planting.