Hardwood mulch allows plenty of room for air circulation, and is not easily washed away with rain, making it great for areas where thick layers of mulch is needed. Hardwood mulch does not attract termites and is good for suppressing weeds. Due to its slow decomposition rate, hardwood mulch is among the longest lasting mulches available, and is best used in areas of your yard that do not require regular turning or tilling, which makes it among the best mulches for trees and around shrubs.