The neighbor on the other side of my fence has blackberry bushes that sends up numerous shoots in my yard as well as two 2-3 inch diameter trunks that are threatening fence integrity. I've left notes (she appears to be rather seclusive with no way to reach her door to knock) stating I'd pay to remove or cut them back - no response. So, I thought to dig a 6-10 inch deep trench along fence line and pour in ready-mix concrete. What do you think? Will it work and if so just how deep and wide? Any other suggestions? As for the trunks I thought I'd paint them with something like paint or tar to keep them from sprouting again (I cut them back as much as able).