Roots growing through overlap in barrier
Three or four years ago I installed a 24" barrier to plant some bamboo. I left an inch or two above ground to catch any runners. It is in a large oval shape. It has worked well for a few summers but yesterday I saw some shoots sprouting outside the barrier.
I dug out where the sprouts were. There was four or five long roots that I removed. I dug down to the bottom of the barrier to make sure I didn't miss any. The roots grew in between the over lapping portion of my barrier. I over lapped it probably about a five foot section. In my trench I was able to pull back the over lapping section and cut all the root masses I could get to.
Besides digging it all up to keep it from spreading what are my options? I was thinking of leaving a small trench open so I could see any more runners trying to escape and cut them back as needed.