This invasive plant has escaped gardens and is spreading across Canada
Once you see the plant, you'll see that it's everywhere.
Goutweed: A plant that so aggressive that frustrated gardeners have created an online support group dedicated to trying to control it.
At the time of this writing, it has more than 9,000 members.
This ornamental plant that spreads quickly and is difficult to eradicate, earning it the nickname “gardener’s worst nightmare.”
Some exasperated gardeners are more blunt: A 2023 article by the CBC calls it the “cockroach of the botanical world" due to its extreme resistance to removal.
And yet, in spite of this, the plant — which sometimes goes by the names Bishop's Weed or Snow on the Mountain — is not regulated under Canada’s Invasive Species Act, and remains widely available in garden centres across the country, according to the Invasive Species Centre.
1888 illustraion of goutweed. (Wikipedia/Public domain)
What is goutweed?
Goutweed (Aegopodium podagraria) is a hardy, shade-loving groundcover that sprouts small white flowers in late May and June.
Once established, it spreads quickly via a network of far-reaching, underground rhizomes, or stems, making it hard to get rid of.
Goutweed rhizomes sprouting new shoots. (Drahkrub/Wikipedia CC BY-SA 4.0)
This is something people often learn the hard way: If placed in a garden without deep barriers to contain the underground spread, it can quickly take over a yard.
Goutweed has escaped cultivation and can be found choking out native plants on forest floors in every province.
Originally from Europe and Asia, it was likely brought to Canada in the mid-1800s by European settlers.
It’s already starting to pop up in Canada this year, with 160 observations on iNaturalist in April.
Identifying goutweed
Goutweed has leaves that are divided into groups of three smaller leaflets, which often have slightly serrated edges and a pointed shape.
It’s usually light green and produces small clusters of small, white flowers, similar to Queen Ann’s lace, in the late spring and early summer. Leaves can also contain white variegation.
(Juandev/Wikipedia CC BY-SA 3.0)
Why is goutweed highly invasive?
Some gardeners prefer goutweed because it’s easy to care for, but that exact characteristic is the reason it has become such a problem in Canada, according to the Invasive Species Centre.
It spreads fast in almost all weather conditions and is extremely difficult to remove.
Its adaptability helps it form dense carpets on residential yards or in shaded forests, inhibiting the growth of native plants and reducing biodiversity.
"Once it's in there, you have to get in there and take out every part of that plant. It's not just a matter of cutting off the top," Tim Walsh, horticulturist and nursery manager at Memorial University's Botanical Garden, told the CBC.
Why is goutweed still sold in Canada?
Goutweed remains available for sale in Canada for several reasons, including a lack of regulation, high customer demand for low-maintenance groundcover foliage, and a lack of consumer awareness.
Speaking with the CBC, Angela Way, a St. John’s resident who has been fighting goutweed in her garden for years, says many people don’t know what they’re signing up for when they purchase the plant.
Way told the publication that she bought her home in the winter and didn’t know the weed was growing on her property until spring.
After several unsuccessful attempts at removal, she covered her garden with black tarps to limit the plant’s access to sunlight. In 2025, she told the CBC she would have to keep the tarps in place for two to three years.
A goutweed plant with varegated leaves. (Gregory Philips/Wikipedia CC BY-SA 3.0)
How does goutweed spread?
Goutweed spreads plenty fast on its own, extending its reach by upwards of 70 cm a year.
It’s also spread through contaminated gardening equipment, improper disposal, and tiny seeds that can spread with the help of wind, water, or animal fur.
Getting rid of goutweed
Goutweed is difficult to pull out due to its underground rhizome network, so if you have it on your property, you’ll have to pack your patience, because removal can take years.
Even tiny root fragments can regrow, so people often resort to using tarps or thick cardboard and mulch to smother the plants and block sunlight.
When disposing of plants, make sure they have been left out in the sun for several weeks first, but avoid composting altogether.
While herbicides can be effective, several applications may be required.
Header image: File photo courtesy of the City of Toronto/Facebook