Broad-spectrum herbicides severly injured container-grown (Cotoneaster divaricata, Rehd. & Wils. and Euonymus fortunei, (Turcz.) Hand-Mazz. cv. Coloratus, because of rapid leaching into the root zone as a result of the porous peat-perlite medium. Injury was eliminated when activated carbon at 0.75 kg/m3 was mixed into the medium. Weed control was achieved by applying a 2.5 cm layer of the medium containing herbicide (but not activated carbon). The most effective herbicides were dichlobenil (0.44 g/m2), dichlobenil (0.44 g/m2) plus trifluralin (0.22 g/m2), or simazine (0.44 g/m2).
Received for publication March 12, 1973. Journal Article 4341, Purdue University, Agriculture Experiment Station.