Annual ryegrass in rotation with summer cover crops will provide organic matter and eliminate weeds from the area. Cultivation and spacing. Some growers have minimized weed competition with a combination of early cultivation and narrow between-row spacings. This can be effective if the crop gets a head start on the competition. If the crop's growth is impeded in any way, the weeds will take over.
Regular cultivation can limit weed competition between rows.
However, cultivation can injure the roots of some cut flowers and will cause some soil water loss due to evaporation. Mulches are another option. According to Dr. Andrew Senesac of the Long Island Research Laboratory, black plastic, remay spun and glued, and Weedblock can be utilized successfully in controlling weeds around field grown herbaceous perennials. In some studies however, Achillea and Stachys flower production was reduced by these mulches due to the physical restriction of the spreading shoots. Spreading perennials that do not produce adventitious roots did not show any significant yield differences from the controls.