Mulch comes in different types and textures. You may want to use it for the three main reasons: soil moisture retention, weed suppression and aesthetics. It can also help keep the soil temperature steady. Choosing the right type for your location will help keep it in place with the look you like. In high wind areas bark chips and cocoa shells usually blow away – there goes your work- so shredded bark or pebbles is a better bet. In fire danger areas it’s being recommended by fire folks to not use wood mulch near your home. Rock mulch, usually pea gravel, can be used and actually some xeric plants like this better plus it can help reduce soil erosion on slopes.
Wood mulch is good for plants that need moderate water and for winter protection. Clean shredded cedar or pine looks so tidy when newly spread around your perennials and bushes. About 3 – 4 inches deep is needed. Be careful not to mulch up to the base of plants but leave some breathing space instead. A friend and I compared mulch and no mulch when we happened to plant the same pre-planned perennial garden last summer. My plants grew larger and faster and filled in but she was not out there weeding and may have used less water. Now that mine are mature size I may mulch this summer to save on weeding. I did plant ground covers to serve as a living mulch for weed suppression and this helped quite a bit. Another option is no mulch, which almost all of a vegetable or edible plants garden will be. Using clean straw or dried untreated grass cuttings under strawberries or veggies which grow on the ground like squashes can help the fruit grow on a dirt free surface. Easier to pick and eat. Gardeners turn in the straw or clippings when they put the bed to rest in fall. Black sheet weed mat can give you soil warming, moisture retention and weed suppression benefits before you plant tomatoes or other plants. Weeds and grass can continue to sprout and grow under it so be sure to remove their roots from the soil when you clear out and prepare your planting area. Plastic sheeting is not recommended since water can’t get through. Wood mulches can take nitrogen from the soil as it breaks down so adding a light amount of nitrogen to the top layer of soil prior to spreading the mulch is often done. As the organic mulch breaks down it adds to the soil structure and the living organism microclimate. Whatever mulch you use will need annual refreshing. It’ll give you something to do in spring or fall.