Planting Grasses under a Black Walnut

Question: I have a large black walnut tree in my front yard.  I was wondering if you could tell me what grasses would be able to tolerate the affects of juglone.  I live on the south end of Blaine and have the typical sandy soil of the sand plain.  The yard has both sun and shade.

Answer: As far as I know and have experienced, all the grasses are ok with juglone, the chemical from black walnut trees. Many monocots and the whole grass family seem to be immune to juglone, so I think you can try most any grass. A black walnut tree does not have much shade, that is a plus as well. Now you just have to deal with the tree root competition and dry site!! So I would try the drought tolerant grasses, such as blue grama, sideoats grama, little bluestem or prairie dropseed.


Red fall color on Blue HeavenTM little bluestem with prairie dropseed in the foreground.

About grasstalk

University of Minnesota Professor and Extension Horticulturist
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2 Responses to Planting Grasses under a Black Walnut

  1. Jay Petrow says:

    I too have a large black walnut tree hovering over my property and have tried to plant miscanthus and panicum under it with poor results. The grasses survive but are dwarf versions of the same grass planted on other parts of my property. Under the walnut tree the miscanthus grows only to about 18 inches while others when planted further away from the walnut tree are a much taller 5-6 foot grass. Same plant, different environment.

  2. grasstalk says:

    Thanks Jay for your comments and experience. It does sound like the black walnut has affected the growth of the miscanthus on your property. Additional factors are root competition for water and nutrients and of course, the shade and limited light under the black walnut. Monocots (which includes all grasses) seem less susceptible to juglone, but I am not aware of any research in this area specifically on miscanthus. so juglone along with the water and light competition could all be affecting your miscanthus. Thanks again for your comments. Mary Meyer

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