Meaning

noun a protective covering of rotting vegetable matter spread to reduce evaporation and soil erosion

verb cover with mulch

originProbably from Middle English melsche, molsh (“soft”), from Old English melsċ, milisċ (“mellow; mild; sweet”, literally “honeyed”), probably from Proto-Germanic *mili (“honey”). Compare Icelandic milska (“a honeyed beverage”).

Etymology from Wiktionary, CC BY-SA 3.0