Question
I have three maple trees that put out numerous sprouts near the base of the tree.  I have to cut them off several times during the spring and summer.  Is there any way to prevent them returning without harming the tree?  Would it do any good to cover the area with black plastic to block the light?

Answer
Cutting the sprouts is usually the best method. If you were to use a herbicide the parent tree may be damaged. You might try a growth retardant. Have not heard it used on sprouts but it is used to slow or stop growth of bushes and trees. They are sprayed on the sprout foliage and the growth is slowed way down but they will not damage the tree. I would try it it can not harm the trees and there is no reason it will not work. Check with your local tree nursery for these growth retardant products.

The plastic will heat up the lower trunk and the root collar and damage or kill the tree.