| B. Rosie Lerner
Preventing Fruiting in Woody Plants
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.