The Enemy: Perennial pepperweed (Lepidium latifolium)

Strategy: A perennial plant native to southern Europe and western Asia, this is a beautiful plants introduced into the country as an ornamental and now has become a noxious weed. It has small, white flowers that grow in small clusters at the terminal end of the shoot. Leaves are extremely waxy, with a prominent, whitish mid-vein. It has an extensive root system and grows thick enough to completely cover the ground and surrounding vegetation. Perennial pepperweed is green throughout the summer and grows 3 to 6 feet tall.

Attack: This plant will crowd out any desirable vegetation in a few years. Due to its extensive root system, other plants cannot re-grow in the area. The thickness of the above-ground growth prevents sunlight from reaching other plants. Many people find this plant attractive so they pick it, take it home and then restart a problem. Although this mustard is not toxic to animals, they do not desire it as a forage.

Defense: It is primarily found along ditch banks and rivers. When it is newly established, mechanical control can be effective. There are no biological control insects available yet. Herbicides such as Telar XP, Escort XP and Opensight are products of choice. In open fields and wastelands, waiting until the plants are in the bud stage is the prime time to spray. Also, adding a silicone-based surfactant will help spread the herbicide as well as help it penetrate through the waxy leaf surfaces. It looks like many mustards that grow everywhere so call you local weed authority to properly identify the plant.

To learn more, call Bonneville County Weed Superintendent Jeffrey Pettingill at 208-529-1397 or email weeds@co.bonneville.id.us.

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