Perennial (Broad-leaved) Pepperweed
A perennial herb, perennial pepperweed (Lepidium latifolium) is native to Europe and Western Asia, and may have been introduced accidentally. It grows 2 to 5 feet tall and has clusters of four-petaled white flowers.
It typically invades higher-elevation parts of coastal wetlands, though in recent years it’s been found inland along highways. It can change soil conditions in a way that enhances its ability to displace native plants.
For seedlings and small colonies of established plants, hand pulling can be effective, but you may need to pull for several years. Bag and compost pulled plants to avoid spreading seeds. Glyphosate-based herbicides are effective when applied as a foliar spray around the time of flowering (June and early July). Because it almost always grows in areas subject to the jurisdiction of the Massachusetts Wetlands Protection Act, anyone planning control measures should first check with the conservation commission of the town where the work will occur, and only apply herbicides registered for use in these areas. Always read and follow the directions on the label when using herbicide.
Perennial Pepperweed Control Project
Since 2006, Mass Audubon, the U.S Fish and Wildlife Service, the Massachusetts Bays Estuary Program, and the Newburyport Gulf of Maine Institute team have battled the invasive Perennial Pepperweed in the Great Marsh on the northern coast of Massachusetts. Learn More