Mulch helps stop soil from compaction during downpours. Loose, uncompact soil yields healthy plant roots. Also, mulch slows water runoff and reduces soil erosion. Which means the beds absorb more rain water, so you don’t have to water as often. Suppresses most weeds and makes pulling weeds that do sprout easier to pull. Reduces disease outbreaks by preventing soil from splashing onto plants leaves. Gives your flower beds a polished look. Gives the most basic landscape an enhanced polish effect. And for the winter months it will protect shallow-rooted plants by insulating the soil against extreme temperatures.
How much Mulch should you use?
1) Thickness should be 2-3 inches; if your area is slow draining use a thinner layer of 1-2 inches. Too thick of a layer could cause plant rot.
2) When placing your mulch, go out past your plant drip-line (outermost point of the leaves). And for your perennial crowns, shrubs and tree trunks place mulch back 2- to -4 inches to prevent plant rot.
3) After you are satisfied with your placement and coverage, water the mulch. This keeps dry mulch from absorbing soil moisture (and stealing it from plant roots) and it helps anchor lightweight from wind blowing it away.