We have a 50 year old English walnut tree and wanted to landscape around it with stone and fill in with dirt and plant flowers on top, then I read that it will kill some trees.

Is this true?

  • That will kill any tree. No soil or grass or weeds or mulch on that bark at all. Forget using rocks for borders. That is like making condominiums for all kinds of insects, slugs, snails, pill bugs...earwigs..Good move to ask first. That tree is gold!
    – stormy
    Jun 7, 2018 at 7:11

2 Answers 2


Yes it is. If your tree has buttress roots that stick out above the soil, these should not be covered in any way, and the soil level around the trunk should not be raised even if buttress roots are not present. If you want to landscape with stone nearby, care should be taken not to destroy any roots that belong to the tree which are beneath soil level. Any of these changes or damage to the roots can result, ultimately, in the death of your tree.

It is also unwise to plant under the canopy of a walnut tree - they produce a substance called juglone which can be toxic to other plants, see information here https://extension.psu.edu/landscaping-and-gardening-around-walnuts-and-other-juglone-producing-plants

  • Creosote also poisons the local area to keep encroachers at bay. There is a lot more going on with plants you'd think! What with planning murders and all.
    – Tim Nevins
    Jun 6, 2018 at 18:58

The received wisdom is that you can't plant anything underneath a walnut tree, however lots of people have beautiful, verdant lawns under walnut trees including this one outside the 200 year old "walnut tree cottages" just up the street from me.

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