Lepidium latifolium

Lepidium latifolium is a perennial weed of coastal wetlands, inland waterways, irrigation ditches, rangeland, hay meadows and waste areas, and tolerates saline/alkaline environments. Prolific seed production, rapid and substantial vegetative growth, creeping rhizomes with high storage capacity, potential for bud production at each node, and deep rhizome penetration have contributed to the widespread establishment of L. latifolium. Canopy height and density, combined with an accumulation of dead stalks in wetlands, has interfered with the regeneration of native plants and the habitats of birds and other animals, as well as hampering control of mosquitoes.. In rangelands and pastures, L. latifolium can compete with native species and reduce forage quality. (Francis & Warwick, 2007)

Decaying litter may increase sodium content in surface soil, with a potential negative impact on salt-intolerant species. (Francis & Warwick, 2007)

On a wildlife refuge in Oregon, L. latifolium displaced 5 and 10% of the native vegetation in the meadow and grass/shrub uplands, respectively; both are critical habitats for nesting aquatic birds and because hay from infested meadows is not marketable, contamination by L. latifolium has jeopardized haying programs on the refuge, which is also required to maintain a supply of short and medium grasses for sandhill cranes (Grus canadensis L.), shorebirds and waterfowl (Kilbride et al. 1997). The greatest damage from displacement of high quality forage grasses and sedges in western United States rangelands has been a reduction in protein content and digestibility of hay; while in unmowed areas the accumulation of persistent non-degraded dead stalks from previous seasons has both inhibited grazing, and had a negative impact on nesting sites (Young et al. 1995a, b; Renz 2000; Krueger and Sheley 2004). Lepidium latifolium also acts as a “salt pump”, transporting salt ions through the roots and depositing them near the surface in dead leaves and stalks, creating a hyper-saline soil environment (Blank and Young 1997b. (Francis & Warwick, 2007)