Can Black walnut trees and American Hazelnut trees coexist? - Ask Extension
I have 2 black walnut trees on the north side of my house in Eagan. They are about 30+’ tall. I love them. I am wondering how far away from the blac...
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Can Black walnut trees and American Hazelnut trees coexist? #762288
Asked July 17, 2021, 3:26 PM EDT
I have 2 black walnut trees on the north side of my house in Eagan. They are about 30+’ tall. I love them. I am wondering how far away from the black walnut trees I need to plant 2 new American Hazelnut trees, also in part shade on the north side of my house. I have not purchased the hazelnut trees yet but would like to in the fall.
Thank you!
Dakota County Minnesota
Expert Response
Hello Linda, happy to help.
It seems that the hazelnut tree is resistant to the juglone that walnut trees produce; so that is not an issue. Also, hazelnut trees are fine in part shade areas; so the north side may be fine since it's fine for the walnut trees.
The final consideration is how close the hazelnut tree can be located to the walnut trees and not be affected by root competition for water and nutrients. A hazelnut tree can reach a maximum width of 13 feet and a black walnut tree can reach a max width of 75 to 100 feet. Tree roots actually extend much farther than the drip line of the tree as demonstrated in the diagram below showing how shallow but extensive a typical tree's roots are relative to its canopy.
Since your walnut trees have not reached maturity, the hazelnut tree may be able to compete for water on an equal footing if located outside of the nearest walnut tree's drip line by about 12 feet (5 ft beyond the walnut tree's drip line plus 7 feet for the maximum mature spread of the hazelnut on the side closest to the walnut. By the time they each reach maturity, they should be able to sort out the competition much like trees in the forest. But this is only a guess.
Good-luck!
It seems that the hazelnut tree is resistant to the juglone that walnut trees produce; so that is not an issue. Also, hazelnut trees are fine in part shade areas; so the north side may be fine since it's fine for the walnut trees.
The final consideration is how close the hazelnut tree can be located to the walnut trees and not be affected by root competition for water and nutrients. A hazelnut tree can reach a maximum width of 13 feet and a black walnut tree can reach a max width of 75 to 100 feet. Tree roots actually extend much farther than the drip line of the tree as demonstrated in the diagram below showing how shallow but extensive a typical tree's roots are relative to its canopy.
Since your walnut trees have not reached maturity, the hazelnut tree may be able to compete for water on an equal footing if located outside of the nearest walnut tree's drip line by about 12 feet (5 ft beyond the walnut tree's drip line plus 7 feet for the maximum mature spread of the hazelnut on the side closest to the walnut. By the time they each reach maturity, they should be able to sort out the competition much like trees in the forest. But this is only a guess.
Good-luck!
