Weed Management Guide for Herbaceous Ornamentals
This chapter is intended to help the commercial grower and landscaper choose a safe and effective weed management program for herbaceous ornamentals. Weed management is an integral and important part of all commercial production of herbaceous ornamentals. There are several herbicides available that can be used safely and legally to control weeds in herbaceous ornamentals. Herbicides are commonly classified by their mechanism of action and use pattern. Preemergence herbicides are applied before weeds emerge and generally provide residual control of weed seedlings for several weeks. Postemergence herbicides, applied after the weeds have emerged, are of two types. Contact herbicides kill only the portion of the plant that is actually contacted by the herbicide. Systemic herbicides are absorbed and move through the plant. Most of the preemergence herbicides that are registered for herbaceous ornamentals act by inhibiting the normal root development of small weeds before they emerge.