Goutweed

Description

Goutweed (Aegopodium podagraria) is an invasive perennial plant native to Europe and northern Asia that was introduced to North America in the mid-1800s as an ornamental plant. Popular as a low-maintenance groundcover, goutweed spreads rapidly through an extensive network of underground stems called rhizomes and can regrow from small rhizome fragments. Once established, it can form dense patches that crowd out native vegetation and dominate the understory of forests and other natural areas.

  • Scientific name: Aegopodium podagraria 

  • French name: Égopode podagraire 

  • Common name(s): Bishop’s goutweed, ground elder 

  • Regulatory Status: Goutweed is not a federally regulated species. Despite its negative impacts, there is currently no ban on the sale of this invasive plant in Canada. 

Image of a field of goutweed

© E_Verbitsky via iNaturalist.org, used under CC-BY-NC

Introduction and Spread

Goutweed is native to Europe and northern Asia. It was introduced to North America in the mid-1800s as an ornamental plant. It was first recorded in Canada in 1902. It continues to be a widely popular ornamental plant due its adaptability, versatility, low maintenance requirements, drought tolerance and its ability to spread rapidly. Humans are the primary pathway of spread for goutweed as most infestations originate from the intentional planting of this species. Dumping yard waste into natural areas, which is typically illegal, is another way that goutweed is introduced to natural areas. Goutweed can regenerate from a small rhizome fragment. 

Goutweed occurs in at least 29 US States Maine south to Georgia, west to Minnesota and Missouri, as well as in the Pacific northwest in Montana, Idaho, Oregon, and Washington. The importation and sale of goutweed is prohibited in Connecticut, Maine, Massachusetts and Vermont. Goutweed has spread across most of Canada with the exception of Newfoundland and Labrador, Yukon, Nunavut, and the Northwest Territories.

Habitat

Goutweed can be found in a variety of habitats. However, it prefers partial sun to full shade and well-drained soils. It typically established in the understory of forests where the ground layer has been recently disturbed or the soil is bare (Lind 2011). Goutweed can be found in a variety of disturbed environments such as abandoned fields, meadows, pastures, forest edges, roadsides and ditches. In North America, it can be found in upland hardwood forests, riparian areas, forest borders, floodplains, wetlands and along the edges of bogs (Waggy 2010).

Identification

  • Height and Stem: Goutweed grows up to 1 m tall. Its stem is erect, hairless and hollow. 

  • Leaves: Goutweed has compound leaves. They are divided into 3 groups of 3 leaflets (ternate). Leaflets are often not fully separated, giving them a mitten-like appearance. The leaflets are somewhat oval-shaped with coarsely toothed margins. Many of the leaves are basal where the leaf stalk attached directly to the rhizome. Basal and lower leaves are larger than upper leaves. The lower leaves are also doubly compound, totaling up to 9 leaflets per leaf. The leaves are mostly hairless and medium green or variegated (blue-green with creamy white margins). 

  • Flowers: The flowers of goutweed occur in flat-topped compound umbels (umbrella-shaped flower clusters). They lack bracts (modified leaves). Each umbel is made of 10 – 20 umbellets each of which can have 15 – 25 individual flowers. The flowers are small, white and have five petals. 

  • Fruits: Each flower produces a tiny, brown fruit called a schizocarp. It is oblong to oval shaped, laterally flattened and small (3 – 4 mm long). 

  • Roots: Goutweed has an extensive underground root system that is composed of branching, white rhizomes. New plants can grow from broken rhizome fragments. It can spread up to 70 cm per year through its rhizomes.

Image of goutweed flower

Goutweed flower

Image of goutweed leaves

Goutweed leaves

Image of goutweed seeds

Goutweed seeds

Impacts

  • Goutweed is an aggressive invasive plant that, once established, creates dense mats of vegetation, that displace native species. It reduces light levels near the forest floor that reduce seedling recruitment and germination (Schimpf et al. 2013).  

  • It can invade closed-canopy forests and dominate the forest understory and outcompete native plant species, including species at risk (Waggy 2010).  

  • It may alter decomposition and nutrient cycling in forests and woodlands. 

  • Parts of goutweed are poisonous if ingested and handling the plant can cause skin irritation.

Life cycle

Goutweed predominantly spreads via rhizomes. Its leaves begin to develop in the early spring and are usually fully expanded by May. They tend to stay green into the fall and until the first frost. In early spring, the leaves are often green below the snow. Its flowers bloom from June to August and the fruits ripen from mid-July to September. Goutweed can also spread via seeds which require a long period of cold stratification to germinate. However, goutweed does not form long-lived seed banks (Lind 2011). Its rhizome network can spread up to 70 cm per year away from the parent plant. The plant consumes all its carbohydrate reserves in the spring (Meyer and Hellwig 1997). 

What You Can Do

You can help prevent the spread of goutweed by:

  • PlayCleanGo: To prevent the spread of invasive species, stay on designated trails to prevent spreading, clean equipment, vehicles and clothing after visiting infested areas, and dispose of plant material properly. Cleaning equipment and vehicles that have come into contact with goutweed, and educating the public about the importance of not moving plant materials, can help prevent the spread to new areas.  

  • Educate: Learn to identify goutweed  and spread awareness about the ecological risks posed by goutweed and encourage responsible practices in your community.  

  • PlantWise: Do not plant goutweed or other invasive species. Choose native or non-invasive alternatives. Dispose of yard waste properly and do not dump it into natural areas. 

  • Reporting: Report goutweed and any invasive species to the appropriate provincial authorities such as provincial invasive species councils or report using free tools such as EDDMapS and iNaturalist.  

Other Resources

  1. Lind S. 2011. Aegopodium podagraria L. Available from: https://dnr.wisconsin.gov/topic/Invasives/fact/BishopsGoutweed  [Accessed 2025 August 11].  
  2. Meyer K, Hellwig FH. 1997. Annual cycle of starch content in rhizomes of the forest geophytes Anemone nemorosa and Aegopodium podagraria. Flora. 192(4): 335-339. 
  3. Waggy MA. 2010. Aegopodium podagraria. In: Fire Effects Information System [online]. US Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Available from: https://www.fs.usda.gov/database/feis/plants/forb/aegpod/all.html [Accessed 2025 August 11].  
  4. Schimpf DJ, Garske SC, Regal RR. Persistent Effects of Herbaceous Species on the Infectious Lethality of Soil for Conifer Seedlings. University of Minnesota, Duluth, MN. Available from: https://conservancy.umn.edu/bitstreams/5a9073f8-a4e9-4f4e-917c-f83f7391cd3c/download [Accessed 2025 August 11].   

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