Mature River Birch Root Problem - Ask Extension
I have a 20+ year old five trunk River Birch tree. It is healthy. I had an arborist come last year and trim it back quite a bit. Unrelated to that, my...
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Mature River Birch Root Problem #338366
Asked July 01, 2016, 11:01 AM EDT
I have a 20+ year old five trunk River Birch tree. It is healthy. I had an arborist come last year and trim it back quite a bit. Unrelated to that, my concern is that there are large roots growing across the top of the ground. I understand that this is due to shallow watering practices over the years. Some of the roots that are visible and looking like they are headed right for my neighbors house and maybe my house so I am concerned that the roots might damage the houses and of course the surface roots are ruining their grass. SO i have two questions:
1. Can I cut the roots if I do it outside the area of the canopy?
2. I am thinking of removing the grass around the tree and planting flowers, hostas, etc.so that I don't have to mow over the roots which is a hassle. If I do that, how many inches of top soil could I put on top of the root area without negative affects on the tree?
Thanks,
Ed Wakem
651-373-0.386
Dakota County Minnesota
Expert Response
The surface roots cannot be cut off without the possibility of significant harm to the health of the tree. Trees need oxygen as well as water and soil and that is why roots grow near the surface. 1-2 inches of soil can be added as a top dressing. A perennial bed under the tree is an excellent idea. It is very good for the tree because turf is a strong competitor for water and as the canopy gets denser there is less light and grass gets shaded out. I think perennial beds are much more attractive with the bonus of being good for the tree. Insert the hostas between the roots rather than adding more soil. If you remove the grass take care to preserve as many surface roots as possible. The tiny fibrous roots are what take up water.
