Why mulch in the fall? By mulching in the fall you will keep the soil warmer for a longer time helping the roots of plants grow later in the season.  Also, mulching helps keep moisture in the soil and does not let the sun and wind dry it out.  Mulch adds a nice look to your landscape and keeps the lawn mowers and weed trimmers away from the base of trees so there is not accidental damage.  As mulch decomposes it adds organic matter into the soil, which helps improve soil structure.  Mulch also deters the growth of weeds which helps with maintenance. Remember that you only need 2-4 inches of mulch around your plants.  If you were going to mulch and realized you already have 2-4” of mulch, work up the mulch and this should make it look better and keep it from compacting too much.  Too much mulch can be detrimental to plants and trees.  Mulching too deep can keep soil too wet and not let oxygen into the soil.  Keep mulch away from trunks of trees and shrubs as this can be habitats for rodents and also stress the tissue and lead to disease and insect problems.  By mulching correctly you will save time and help your plants out as well.