The main use of the plastic or fabric would be to discourage weeds from getting established in the beds. The plastic material simply does not allow moisture to penetrate and also does not promote a free exchange of oxygen. These factors can cause problems for many ornamentals and during a stress period, weak plants may die. The landscape fabrics will allow moisture to penetrate and also not inhibit oxygen exchange. The latest research at NCSU rates the usefulness of landscape fabrics very high in conjunction with an organic mulch.
Many gardeners like to add plants in the natural area.
Naturalized understory trees such as dogwood, redbud, silverbell or snowbell can be added. Azaleas, rhododendrons, and other flowering shrubs also compliment these mulched areas. Perennials and low growing, shade loving annuals may be added to the outside edges to complete the design. Published by North Carolina Cooperative Extension Service Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability.