We recently cut down a row of old lilac bushes that were becoming unsightly. We left about a foot stump on the lilac bushes and put Tordon on the stumps hoping they will die and we can pull them out. We want to replace the lilacs with a row of Thuja trees so we still have the privacy and windbreak. How long do we need to wait to remove the stumps and plant the trees?
Replanting a Windbreak
Certified GKH Gardening Expert
You will need to spray the stump liberally with a herbicide.
This will move throughout the system and kill the roots.
You will need to then dig up the roots.
Watering the ground around the tree will help loosen the root system.
Work in a circle to pry the root ball from the ground.
After removing the root ball and roots, fill the hole with top soil.
The amount of time it will take to kill the tree will depend on the concentration of the herbicide and the size of the tree.
It can take any where from 1 to 6 weeks according to my research.