Killing Weeds Around Hosta and Azaleas?

Why a thin layer of mulch? Mulch should be at least 3-4 inches deep to block weeds. As it decays, it should be top dressed yearly, if needed. Some people place a layer of newspaper under the mulch to help block weeds, but this depends where you live. I live in the south, where we get in a drought every year and the soil is dry at least 18 inches down; newspaper stops rain/water from reaching the soil and the plants roots, and the plants bake--no matter how moist the soil is when put it down.

I find that a nice deep mulch does best. I just pull any weeds that sprout every spring. The first few years are the hardest; after that, the weeds get thinned immensely.