Fruit trees and small fruits

How to Prevent a Walnut Tree From Bearing Nuts?

All those fallen walnuts can be quite an annoyance. Photo: thehorse.com

Question: What product could I use to treat my black walnut to prevent it from producing nuts? The nuts really upset my neighbor. It’s a magnificent tree, 60 feet (18 m) tall, but nuts are unwanted.

Jean Lafontaine

Answer: This is not something most gardeners would consider doing, but it turns out it is quite possible.

Bottle of Florel

There are plant hormone products that can prevent trees from producing fruit (and nuts are fruit). These products, like Florel Growth Regulator (active ingredient: ethephon) and Fruitone N or App-L-Set (naphthalene acetic acid or NAA), essentially overdose flowers with hormones and can therefore cause the fruit to abort. They’re mostly used in orchards to control fruit production, but can be used in the home garden.

None of these products is specifically recommended for walnut trees, but they are known to work on a wide variety of trees, from apples to willows and horse chestnuts and so you’ll probably need to experiment a bit. Usually, they need to be applied around the middle or the end of the flowering period or sometimes just as the fruits start to form. An application at the wrong time may have no effect or may even stimulate increased fruit production. So, for the first year, you may have to limit your treatment to individual branches to find out at what point the product is the most effective on walnut trees.

Also, be aware that these products can disrupt the growth of the tree, causing, for example, changes in its branching. Again, you have to try them out to see.

You’ll have to cover yourself with protective clothing from head to toe and keep other people and pets away from the area during treatment. It may be necessary to cover other fruit trees in the area with a tarp while spraying. And it will take a powerful sprayer to reach all the branches of a 60-foot (18-m) walnut tree!

Unless there are a lot of orchards in your area, in which case you might find one of these products in a local agricultural store, you’ll probably have to order these plant hormones online.

But…

Nut gatherer with green walnuts inside
A nut gather makes picking up walnuts and fallen fruit simple. Photo: hendricksfeed.com

That’s a lot of effort to keep a neighbor happy. Have you ever considered offering to go pick up the nuts that fall on their property instead? With a nut gatherer, it’s easy to quickly harvest nuts from the ground.

Or, if no compromise seems possible, it might be wiser to cut the tree down. Then you could plant another tree … well away from the property line. When a tree is in the wrong place, removal is often the only logical solution.

Larry Hodgson is one of Canada’s best-known garden communicators. After studies at the University of Toronto and Laval University where he obtained his B.A. in modern languages in 1978, he succeeded in combining his language skills with his passion for gardening in a novel career as a garden writer and lecturer. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He is a regular contributor to and horticultural consultant for Fleurs, Plantes, Jardins garden magazine and has written for many other garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening, Rebecca’s Garden and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 50 other titles in English and French. He can be seen in Quebec on French-language television and was notably a regular collaborator for 7 years on the TV shows Fleurs et Jardins and Salut Bonjour Weekend. He is the President of the Garden Writers Association Foundation and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. An avid proponent of garden tourism, he has lead garden tours throughout Canada and to the gardens of over 30 countries over the last 30 years. He presently resides in Quebec City, Quebec.

3 comments on “How to Prevent a Walnut Tree From Bearing Nuts?

  1. That is nuts!
    You can eat or sale them.

  2. The nuts are hard to extract but delicious. We used to crush the outside pulp by driving on them, then crack the hard shells and make highly aromatic baked good with the flesh. It seems a shame to kill a tree, when collecting the mess for your neighbor and sharing the bounty might be a blessing in disguise.

  3. Like you mention, timing is critical. I never liked this stuff, but we used it in olive trees in landscape situations. (If I had an olive tree in my garden, I would want all the olives I could get.) On the farm, we used in on the rhododendrons, because it is faster than pinching. It does not work well for rhododendrons though, and must be a rich (and caustic) concentrate.

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