Tie a string or bend a wire around the pot tight enough so it won't slip off the pot, but loose enough to tie strings to it. Then tie your buds to the string instead of the pot. If that made sense
I had a similar idea but using a Velcro strip wrapped around the lip with another running across the surface and fastened to that one from each side. That would stabilize the encircling one. Then you can easily tie branches down with more Velcro. I buy it in rolls and use hem everywhere.
A heated nail would pierce the plastic if you're brave and careful. That would give you tie off holes for twine or twist ties.