Goutweed in flower Goutweed in flower

Goutweed (Bishop's Weed)

Aegopodium podagraria

2019 Status in Maine: Widespread. Severely Invasive.

Description: Herbaceous, perennial ground cover, 1-2' tall, with many common names. Leaves: Compound with variable triternate leaflets; pointed leaflets have serrate margins. Most leaves are basal with long petioles. Wild type is a medium green color while the variegated form is pale bluish breen with white margins. Flowers/Seeds: Typical carrot family flowers; 2-5" diameter umbels of tiny white flowers atop 2-3' stalk. Plants require at least partial sun to flower. Seeds are brown, small and flat. Roots: Fleshy long white white rhizomes, like quackgrass (Elymus repens).

Native range: Southeastern U.S., Pennsylvania to Georgia, west to Missouria (Appalachia; Ozark Plateau). How arrived in U.S.: As an ornamental.

Reproduction: While research shows that goutweed's insect pollinated flowers can produce viable seed, seedlings are rarely encountered. Its branching network of rhizomes allows it to grow aggressively away from plantings or colonize a new site via contaminated soil.

Habitat: Moist soil and light shade are preferred garden spots, but goutweed is content in many habitats. It typically enters forests from runaway plantings or via fill contaminated with rhizome fragments.

Similar native species: Golden alexanders (Zizia aurea) has somewhat similarly shaped leaves but yellow flowers. Anisewood and sweet-cicely (Osmorhiza spp.) also have somewhat similarly shaped leaves but are anice-scented, fruits (seeds) are elongated, and leaves and stems often have hairs. Neither of these species grows with the dense habit of goutweed.

Similar non-native species: Other weedy members of the carrot family.

Documented Ecological Impacts

Fact Sheets and Identification Links

Control Methods

Hand-pulling will not extract the deeply growing rhizomes, so digging tools are rquired. Dispose of rhizomes in bags in trash to prevent spread*. Repeated excavation will be required. Mowing can slow the spread but is unliekly to exhaust large patches. Poor results are reported for covering with tarps and plastic sheeting. Goutweed is a tenacious ground cover and an excellent candidate for a systemic herbicide application (triclopyr or glyphosate solution). Apply as a foliar spray during the growing season. Good results have been reported for mowing first and then spraying the leafy regrowth. Multiple treatments may be required.

* Correctly dispose of all plant parts † Follow all label directions when using herbicides

Control Technique Video Demonstrations

Goutweed in floodplain setting Goutweed in floodplain setting

Please email invasives.mnap@maine.gov if you have questions about invasive species in Maine