Let’s be brief: Mulch works. Mulch keeps moisture in, reduces erosion and keeps weeds out, or at least makes them easier to pull. And mulch gives the garden a finished, pleasing look, sort of like the icing. Mulch around trees prevents damage from mowers and string trimmers. Some gardeners prefer the no-mulch look. They use massed plants to shade nearby plant roots and the surrounding area and cover any bare soil with ground covers. But gardens with space or areas between plantings need something to cover bare soil.