Posted: 10/01/2015 at 20:29
This is something that is going to cost a lot of time, energy and inclination. If the beds are now mostly grass, I would be tempted to wait until the spring and dig out the clumps of perennials. Move them into a nursery bed and then put weedkiller down. Wait a few weeks then spray again if more green shoots appear. Dig it over and wait a few more weeks if you can. Then replant. Put a thick layer of mulch down and keep an ever vigilant eye on the weeds. Deal with any you see immediately either digging them out or use spot weedkiller. I walk round my garden every morning and try to deal with weeds as soon as I see them. They are pesky creatures.