Chemical weed control in rose nursery fields

In these experiments of chemical weed control in rose nursery fields, cuttings were planted in t he bottom of furrows in lat e December and early January. These were irrigated twice weekly until rooted. A month to five weeks after planting, CMU, DCMU, SES, CIPC, IPC, and alanap were applied to the soil in the furrows. CMU and DCMU controlled all weeds, and the two phenylcarbamates were of only limited effectiveness. Alanap controlled the weeds but caused serious injury to the roses. Treatments of CMU and DCMU applied in April proved to be as toxic to the roses as to the weeds, while three phenylcarbamates applied at that time provided excellent weed control without damaging the roses.

Later in the season, contact sprays were a pplied to the weed growth and to the rose stems without wetting the foliage of the cuttings. Various mixtures of are latively nontoxic kerosene with an aromatic oil and with dinitro butylphenol were tested. All formulations effective against the weeds were found t o be more or less toxic to th e roses. The kerosene-dinitro formulations were somewhat more selective than the oil mixtures. Emulsions of dinitrobutylphenol applied in the same way killed all weeds present except grasses and knotweed. Endothal controlled all weeds present except species of Chenopodium. The rose stems were resistant to a wide range of concentrations of both materials.

DCMU, CMU, phenylcarbamates, DNOSBP, and endothal are promising as practical weed control materials in rose culture.