Abstract: A mulch skirt for inhibiting the growth of vegetation around a tree or post is formed from a single sheet having an initial axial opening and a slit extending from the axial opening to a point on the periphery of the skirt. A plurality of adjustment strips are formed around the axial opening by successive concentric rows of serrations. The mulch skirt can be custom-sized on the site to fit around a selected tree or post by removing an inner portion of the mulch skirt along a selected row of serrations corresponding in diameter to the base diameter of the tree or post with which the mulch skirt is to be used. The mulch skirt may be stabilized by a ring extending around the periphery of the skirt and by anchor pins fastening the ring to the ground.