Influence of perennial pepperweed (Lepidium latifolium) biology and plant-soil relationships on management and restoration

Perennial pepperweed is an invasive noxious weed spreading rapidly throughout a wide range of habitats in the western United States. Shoots form dense monotypic stands with high initial leaf area, dense inflorescences, and deep litter layers that inhibit the establishment of other plant species. Roots store large amounts of carbohydrates for future growth, establish deep into the soil, and are responsible for clonal expansion of populations. In sodic soils, increases in N, Mg, and Ca were observed in invaded compared with noninvaded areas. Several management methods are effective in controlling perennial pepperweed, but success is dependent on age and density of infestations. Knowledge of many factors, including perennial pepperweed's biology and specific characteristics of the infested area, will help in the development of the most appropriate, site-specific management and restoration plans.