Black Walnut Tree
I've been loosing my fruit trees, rasberries, blueberries and several other plants in and around the Black Walnut Tree I planted over 20 years ago. I've decided to remove the Black Walnut Tree. All that is now left is about 8 roots extending in several directions. Do I need to be concerned that these roots will continue contaminating the area. If so, how should I deal with them? Do I need to try and dig them out or is there a product that I can use to kill them like Bonide?
Here is our website info on Black Walnut trees and juglone (the toxin in the roots, etc.): http://extension.umd.edu/hgic/walnut-wilt-juglone-trees-and-shrubs
As you'll read, juglone quickly breaks down. This includes the juglone in all the dead roots. So, no, you do not need to worry about continued contamination, assuming the tree is dead.
If live shoots come up from the stump, you can spray them with an herbicide containing glyphosate or triclopyr. (Read the label carefully!) Or simply keep breaking the shoots off, as this will stave the roots to death, but it's a little slower. Once the tree is dead, the juglone will soon dissipate.
In regards to my Black Walnut Tree. I've completely removed it all that is left is the 8 or 9 roots. Will these continue to contaminate all my plants, bushes and shrubs in and around the area or do i need to use some kind of root killer? The Black Walnut Tree has been completely removed no stump left just the roots.
A root killer will not help your situation. The roots will rot and the juglone will also decompose. The remaining roots should not impact your plants. If for any reason you get black walnuts sprouting, get them removed as soon as possible. Keep the area well watered to enhance the health of the other plants and to speed the decomposition of the walnut roots. vw