How to trim walnut trees

Updated February 21, 2017

Growing a flower garden may be an easy way to brighten a landscape, but growing trees can have a variety of advantages. Walnut trees produce tasty nuts, attract wildlife and provide valuable wood that is used for decking, furniture and other construction endeavours. Trimming or pruning your walnut tree can help to eliminate wood knots and encourage fruit growth, making your tree more valuable for wood and food.

Trim back all branches except for the four or five strongest when the walnut tree is first planted. Trim to encourage strong growth in the few branches left, developing strong leaders to support the tree as it grows.

Prune existing walnut trees between January and early March, before the growing season begins. Trim to encourage fresh growth, which will be an advantage when the growing season starts.

Cut away dead or damaged branches by trimming about 30 cm from the branch collar, or the joint between the main trunk and the branch.

Remove any branches smaller than 5 cm in diameter. Trim away the smaller branches to help to encourage larger and healthier grow-back and to allow more nutrients to reach the larger branches that are more likely to produce healthy fruit. Make these cuts just above the branch collar, which distinguishes the branch from the trunk. Do not cut into the branch collar or it could discourage future growth.

Apply a wound dressing to any cuts larger than 5 cm in diameter. Follow label instructions for application details.


Left untreated, wounds can cause rot or other infection in the tree. Find wood sealant for walnut trees at garden centres, nurseries and some DIY or home improvement shops.


Do not prune more than 50 per cent of total height of the walnut tree. Do not remove more than 25 per cent of the tree's living growth. Such severe pruning can permanently damage the wood and the fruit production of the tree.

Do not use any wood sealant or dressing that is not specifically approved for use on walnut trees. Other paints and chemicals can introduce toxins into the tree's system, potentially destroying the whole tree.

Things You'll Need

  • Shears or saws
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About the Author

Samantha Volz has been involved in journalistic and informative writing for over eight years. She holds a bachelor's degree in English literature from Lycoming College, Williamsport, Pennsylvania, with a minor in European history. In college she was editor-in-chief of the student newspaper and completed a professional internship with the "Williamsport Sun-Gazette," serving as a full-time reporter. She resides in Horsham, Pennsylvania.