How Can I Control Perennial Pepperweed?

Do you want to try controlling perennial pepperweed with cultural control methods?

Do you want to control perennial pepperweed using hand pulling, tillage, and tarping?

Do you want to control perennial pepperweed using mowing and burning?

Do you want to prevent a perennial pepperweed infestation?

Do you want to try controlling perennial pepperweed with chemical control method?

Perennial pepperweed seedlings are easily controlled by hand pulling or tillage, but these techniques do not control established plants because shoots quickly resprout from the vast root reserves. Root segments as small as 1 inch are capable of producing new shoots. The best control with tarping is by using thick, black plastic secured over the infested area for two growing seasons. Mowing and tilling the site before tarping can improve control compared with mowing and tarping alone. It is important to extend the plastic tarp at least 10 feet on all sides of the infested area as creeping roots can spread laterally up to 10 feet.

Mowing and burning are not effective in reducing perennial pepperweed stands, but they help remove accumulated thatch. Perennial pepperweed thatch burns best in winter or spring under dry conditions before initiation of spring growth. Mowing breaks old stems into small fragments and helps prevent the shading of favorable species. Mowing also stimulates perennial pepperweed plants to resprout and produce new growth. Combining mowing with herbicides is an effective control strategy.

Establishing desirable vegetation in disturbed areas is crucial to managing perennial pepperweed and preventing future weed problems. Because perennial pepperweed is very competitive, seed or transplant desirable vegetation after dense perennial pepperweed stands are controlled. Choose vigorous, fast-growing plant species that are adapted to the site. Perennial grasses are a good choice for natural areas and pastures. Grasses are tolerant of some selective herbicides used for perennial pepperweed control and over time form a thick sod that prevents future weed establishment.

Be sure that straw, hay bales, mulch, and crop seed are free of weed seed and propagules before applying them to an area. Periodic surveys of property lines, roadsides, waterways, and riparian corridors help detect new infestations before they become well established. If construction or soil disturbance occurs in infested areas, make sure root fragments and seeds are not transported to other sites. Always clean vehicles, machinery, and clothing after visiting infested areas. If livestock grazes perennial pepperweed, hold the animals in closely monitored paddocks for several days to allow the seed to pass through their digestive system before transporting them to new areas.

Several post-emergent herbicides control perennial pepperweed, but repeat applications are usually necessary for several years to treat resprouting shoots and seedlings. Extended control with herbicides is greatly enhanced by establishing competitive vegetation at the site. In areas with a dense buildup of thatch, mow or burn old shoots before applying herbicides. Herbicide application timing is critical. Herbicides work best when applied at the flower bud stage and worst at the rosette or early bolting stage.

Establishing and maintaining competitive perennial vegetation can dramatically slow the introduction and spread of perennial pepperweed. Vigorous sod-forming grasses, alfalfa, or cropping systems with annual tillage help prevent perennial pepperweed introduction and establishment in agricultural areas. Closely spaced plantings of herbaceous perennials, shade trees, and/or fabric or plastic mulches can help prevent its introduction in ornamentals.