Hi everyone!
I’m working on creating a garden edge along my fence with my neighbor, and I’ve removed the grass from a 40 cm wide strip along the fence to prepare it for planting. However, our fence doesn't go underground, and my neighbor has grass same as me on his side. I’m concerned that their grass might spread onto my side of the garden, i will add mulch after, would this be enough or should i put a root barrier along the fence? I don't want to bother but alson dont want to keep removing grass and have to fix it later on...
Can anyone suggest the best way to prevent this? Should I put something underground or create a barrier to stop the grass from propagating into my garden? I want to make sure I don’t have to deal with unwanted grass growth later on.
If you have any advice, I’d really appreciate it!
Also note I'm planning to add a root barrier between my edge and my grass that's for esthetic too

Thanks in advance!