Goutweed or Bishop's Weed

Fact SheetTreatmentAegopodium podagraria

Invader Images

    • Goutweed forms flat wide clusters of small white flowers
      Goutweed forms flat wide clusters of small white flowers
    • Variegation can occur on leaves. Leaves are compound and toothed, and arrangement is alternate.
      Variegation can occur on leaves. Leaves are compound and toothed, and arrangement is alternate.
    • Goutweed infestation
      Goutweed infestation

Common Look-alikes

    • Native plant, Golden Alexander (Zizia aurea) has yellow flowers and a smaller stature.
      Native plant, Golden Alexander (Zizia aurea) has yellow flowers and a smaller stature.

Identification

Appearance

Aegopodium podagraria is a creeping, herbaceous perennial that can grow to be 15.7-39.4 in. (0.4-1 m) tall.

Foliage

The basal and lower leaves have long petioles. There are usually 9 leaflets per lower leaf, although this can vary. Each leaflet is ovate with an acute or acuminate apex. The bases of these leaflets can be rounded or cordate. The lower leaflets are 1-3 in. (3-8 cm) long and have a serrate margin. The upper leaflets are similar to the lower leaflets, but are smaller and ternate in their arrangement, and have shorter petioles.

Flowers

The white flowers are arranged in umbels that are 2.25-4.75 in. (6-12 cm) in diameter. Each umbel is borne on a long peduncle, and has 15-25 rays that are about 1 in. (2.5 cm) or more in length. The flowers of Aegopodium podagraria appear in June.

Fruit

The brown fruits oblong-ovoid, laterally flattened and 0.12-0.16 in. (3-4 mm) long.

 

***check out the downloadable fact sheet above***

Biology

Ecological Threat

Goutweed is aggressive, forming dense, impenetrable patches that displace native plants and greatly reduce ground-layer species diversity. Its colonies also inhibit the establishment of native tree seedlings. Highly shade tolerant, it is capable of invading closed-canopy forests.

Origin

Goutweed was brought to North America as an ornamental by early European settlers. By 1863, it was well established in the United States. It is utilized as a low maintenance ground cover.

Habitat

Forest, forest edge, riverbank, streambank, meadows, fields, disturbed areas

Life Cycle

Goutweed is an aggressive perennial that reproduces primarily vegetatively through a rhizome system. Seeds require cold stratification to germinate, and the seed bank is short-lived. Seeds usually will germinate the next year after initial dispersal. New foliage appears in early spring and flowers bloom in June with small white umbels. The seeds turn brown when they ripen in late summer.

Management Options

This species is Quarantined: Class B Noxious Weed

***Check out the downloadable treatment sheet above***

    Mechanical Control

    Small patches can be eliminated through persistent hand-pulling, careful to remove underground rhizomes. Rhizomes should be bagged and disposed of to prevent reestablishment. Frequent mowing at short heights can control or slow the spread of goutweed. Doing this early in the year just after the plant has fully leafed out, and covering the entire colony with black plastic sheeting afterwards, is a great way to exhaust its energy reserves.

    Goutweed may also be cut in late summer, after leaf-out, and then covered with plastic.

    DO NOT HOME COMPOST! DO NOT DISCARD IN WOODS OR FIELD!

    Plant fragments will re-sprout.

     Chemical Control

    Systemic herbicides, such as glyphosate, are most effective for goutweed control because they are translocated to the roots, killing the entire plant. Contact herbicides are ineffective because goutweed readily leafs out after defoliation. Be careful not to damage or kill nearby native plants when using herbicides and always follow the instructions on the label.

     

    **Be careful not to damage or kill nearby native plants when conducting management work. And when using herbicides, always follow the instructions on the label.**

    How You Can Help

     

    NATIVE/NON-INVASIVE ALTERNATIVES

    Golden alexanders (Zizia aurea), Canadian anemone (Anemone canadensis), Wild sarsaparilla (Aralia nudicaulis)

    Native Perennials and Shrubs for Vermont Gardens​​

    Choose native plants

    Alternatives to Common Invasive Plants and Characteristics of Select Alternatives