I’ll assume that you’re dealing with ‘false bamboo’ aka Japanese Knotweed. This is a former ornamental that will eventually take over the world. I also moved into a house that had the bed one whole side of the house filled with that stuff. We cut it back for a couple of years hoping that that would kill it but it didn’t. What finally did work was covering the area with a plastic tarp 4 layers thick. I actually used an old pool cover that I found by the side of the road. We made sure that the area was covered right up to the house and out about a foot beyond where the knotweed was growing. We then covered the tarp with a thick layer of cedar mulch so we wouldn’t have to look at the tarp. We left it all summer and the next spring I peeked under only to find weak shoots still trying to grow. We left it covered for another summer. Finally, after two years it seems to be dead. We removed the tarps and dug around. We found a few weak roots that we removed and planted the bed with perennials. Every once in a while a shoot would pop up but we’d dig it out rather than just snapping it off….gotta get those roots. Now, several years later, we seem to have finally won our battle. There are weed killers that will kill it and sterilize the soil for two years but we were afraid that it would get into the roots of some nearby shrubs and kill them too so we went the tarp and mulch route. Be diligent and patient and you get it gone.