Unwelcome Walnut Tree

Asked February 2, 2018, 7:38 PM EST

I have a young walnut tree invading my blueberries. It grew out of nowhere & is really quite handsome but I'm either cutting the tree or moving the blueberries to give them a better chance. They're not doing so great. My question: I know walnuts are a type of plant that inhibits other plants from growing is there anything that might grow around it peacefully?

Washington walnut trees

1 Response

Thank you for your question about your volunteer tree. Black walnut trees contain a substance, juglone, which inhibits growth of a variety of plants, listed here, and blueberries are one of those plants. At the end of that same article is a list of plants that are tolerant of juglone.

Since I don't have a photo of the tree's leaves, I can't tell you whether your tree is a black walnut tree or an English (or Persian) walnut tree. As this article explains, English walnut trees do have some juglone, but not to the extent as black walnut. I've attached photos of a drawing of the black walnut's parts, as well as a photo showing the difference between the two.

BTW, your blueberries might not be doing well because they're competing with the tree for sun, water and nutrients, not a juglone problem. Hope this is helpful. Good luck!