Does anybody know a treatment to suppress patio weeds permanently (or at least for a few years)? I have a rear patio and front block paving which are a problem. I've noticed pedestrianised streets in towns, with similar surfaces, which don't seem to have a problem. Maybe that's partly due to plenty of foot traffic, but areas which don't get much are still OK. Is there something to brush into the cracks? I don't mind if it costs a fair bit if it does a good job.
