Yes — a full 3-inch layer of mulch smothers most annual weeds, but deal with the tall stuff first. Pull or cut anything knee-high so it doesn't poke through, then bury the rest; starved of light, most annuals give up under 3 inches.
Tough perennial weeds are the exception — they can push through a mulch layer and are worth digging out before you spread. Skip landscape fabric under mulch: it blocks the soil benefits as the mulch breaks down, and weeds end up rooting on top of it anyway. At 3 inches, a cubic yard covers about 100 sq ft, so a 5-yard load handles roughly 500 sq ft of weedy beds.
Pick a color from the bulk mulch collection — delivered by the yard, Monday–Saturday.
