Invasive mustards: Hoary alyssum, perennial pepperweed and whitetop

While the unusually wet spring was beneficial to native and desirable grasses and wildflowers, many weed species took advantage of the excellent growing conditions as well. Annual mustards with yellow blossoms were abundant this spring and early summer. While "weedy" and too many "obnoxious", these plants are not regulated by the Montana Department of Agriculture, or "noxious". Three weed species that are regulated and required by law to control are perennial pepperweed, whitetop and hoary alyssum.

Montana Noxious weed status: All of these plants are invasive mustards (Brassicaceae family) nat...