A polyolefin sheet material carries layered segments of a polymer which contains a herbicide such as a 2,6-dinitroaniline. The sheet material can be porous to permit free passage of water. It may be either a perforated sheet or a woven or non-woven material. A desired material is a non-woven fabric of non-biodegradable polyolefin material, such as a geotextile, for example. In order to obtain a root growth-repelling property, the herbicide is blended with a polymer which is attached or bonded to or embedded in the geotextile, or other polyolefin carrier sheet material, in the form of spaced apart layered segments. Diffusion of the herbicide directly into the soil is prevented by a barrier material positioned on, coated on, or otherwise bonded to the layered segments, to encompass surfaces of the segments which are otherwise exposed on the sheet material. Essentially all of the herbicide contained in the layered segments is directed into the soil virtually exclusively by means of its long term migration through the carrier sheet material.