I've been using Preen - a granule that you sprinkle in the beds. It doesn't kill existing weeds, though. And you have to re-apply in 3 months, maybe sooner if you get a lot of rain. But it does make a difference. You will still get a few but nothing like you do without it. And it doesn't touch nut-sedge. I used to pick all the weeds, but my back won't allow that anymore, and you can't use a shuffle hoe in heavily landscaped beds, especially ground-covers like jasmine.