Goutweed is a fast-spreading perennial in the carrot/parsley family (Apiaceae) that forms dense patches through aggressive underground rhizomes. Most leaves grow low to the ground and are attached to long leaf stalks (petioles) that connect directly to these underground rhizomes. Goutweed has compound leaves arranged in three groups of three leaflets, each 3-8 cm long with toothed edges. In early summer, Goutweed produces tall, smooth, hairless stems (40 cm to 1 m high) topped with an umbrella-shaped inflorescence of small white flowers. These umbrella-shaped inflorescences, called umbels, are 6-12 cm across and made up of many tiny, five-petaled blooms.
There are two varieties of Goutweed: non-variegated and variegated. The non-variegated variety, also known as the wild type, has solid green leaflets, while the variegated variety has bluish-green leaflets with distinct white edges.
Goutweed is highly adaptable and grows in a variety of environments. It thrives in full sun to partial shade and prefers moist, well-drained soil. It spreads rapidly in disturbed areas and often takes over forest understories, forming dense patches that displace native plants. You can also find Goutweed in abandoned fields, logged sites, grasslands, meadows, pastures, along forest edges, roadsides, ditches, and near streams or wetlands. Due to its aggressive growth, Goutweed can outcompete native plant species, resulting in a decline in biodiversity. In forests, thick patches of Goutweed can even alter the environmental conditions of the forest floor, making it difficult for native shrubs and trees to sprout and grow.
Both non-variegated and variegated varieties of Goutweed are considered invasive. The variegated variety is commonly marketed as a less aggressive variety. However, it can lose the variegation through a process called reversion. Over time, it reverts to the non-variegated variety. Even without reversion, variegated Goutweed can escape gardens and invade nearby areas. Neither variety should be planted, shared, or used in gardening.
Goutweed was first introduced to North America in the mid-1800s as an ornamental groundcover and herbal remedy. Unfortunately, it is still sold and planted as a groundcover. Goutweed can easily spread from gardens into nearby areas through its aggressive underground network of rhizomes. Broken, fragmented rhizomes can regrow new Goutweed plants. These fragments can remain viable in soil for up to four years. They can be spread to new locations in contaminated soil, on the bottoms of shoes, or through landscaping/gardening tools. Goutweed also produces viable seeds that germinate in bare soil under direct sunlight.
Canada Anemone (Anemonastrum canadense) and Large-Leaved Aster (Eurybia macrophylla) are great native alternatives that can be used as ground covers in shaded areas.
Toothed leaves; compound leaves with three groups of three leaflets, white edges (variegated variety only); 5-petaled white flowers arranged in umbels.
Goutweed was historically used to treat gout and arthritis, which is where it got its name!
Promote the use of non-invasive groundcovers and never plant Goutweed. If you have an infestation of Goutweed, do not give away transplanted plants from your garden. Fragmented rhizomes or seeds may be in the soil, causing further spread.
Managing Goutweed requires patience and long-term effort. Eradication is possible with persistence. It is important not to abandon control measures when plants regrow. Please see the Goutweed Best Management Practices document to learn about different management options. To avoid unintentionally spreading Goutweed, clean off all rhizome fragments, contaminated soil, and other plant material from your boots and equipment before leaving an infested area. If you spot Goutweed, report it on iNaturalist or directly to the NSISC.