Knowledgebase
Hedges near a black walnut tree #679163
Asked January 16, 2021, 10:43 AM EST
Ramsey County Minnesota
Expert Response
The oak is going to be a problem. The Juglone that creates the toxicity is in the roots, buds, and nut hulls. The toxicity is extends beyond the drip line of the tree as much as 50-60 feet from the trunk. This makes the palate of possible plants for a privacy screen somewhat limited. Here is a good article on plants that are tolerant of juglone:Plants tolerant of black walnut toxicity | The Morton Arboretum
I was going to suggest using upright yews because of the partial shade, but I couldn't find anything that said they were tolerant of juglone. Ones that would work would be a screen of upright arborvitae or junipers.
The article above might give you some ideas for some nice plantings under the oak.
Hope this helps.