/mulch/ , n.
1. a covering, as of straw, compost, or plastic sheeting, spread on the ground around plants to prevent excessive evaporation or erosion, enrich the soil, inhibit weed growth, etc.
v.t.
2. to cover with mulch.
[ 1650-60; n. use of obs. mulch (adj.), ME molsh soft, OE myl ( i ) sc mellow; c. dial. G molsch soft, overripe ]