One of the few good things that can be said about knotweed is that it makes a pretty sweet pie, one that tastes a bit like a tart kind of rhubarb, according to various online recipes.
In fact, knotweed is one of the worst invasive plant species in BC, one that is nearly impossible to eradicate and can punch through concrete, menacing roads, bridges and building foundations across Metro Vancouver.
The fast-growing plant was imported to Canada from Asia and sold by local Langley nurseries for landscaping.
A group of researchers at Langley-based Trinity Western University (TWU) has joined an international effort to quell the spread of knotweed, working from their home labs during the pandemic.
TWU students Hannah Merritt, Maria Goncharova, Vanessa Jones, and Virginia Oeggerli have received funding from the Weed Science Society of America and a Trinity Western summer award.
So far, they’ve found that smaller patches of knotweed seedlings don’t grow well in shade, and that planting taller native plants that provide shade could be a way to help prevent knotweed spread.
Biologist Maria Goncharova has been running tests on how well knotweed seeds do in fast- to slow-moving streams.
“We are figuring out what are the hot zones, along the river, that are most likely to be invaded,” Goncharova explained.
Virginia Oeggerli, who is investigating knotweed from the germination stage, has discovered that the seedlings don’t grow well in shade.
“Restoring river areas with large native trees or bushes that provide a lot of shade could be a way to help prevent an area from being vulnerable to invasion by knotweed,” said Oeggerli.
Oeggerli was working on her thesis when classes moved online.
“The greenhouses were outside, and with the proper [health] precautions, I have been able to go in,” she reported.
Oeggerli successfully finished her knotweed research project, and is looking to publish her paper in a scientific journal.
Working at home allowed Hannah Merritt the ability to make multiple observations during the day.
“It’s nice to be able to have [my lab] in my backyard,” Merritt said.
Additionally, the team has still been able to go out and look at knotweed species in the natural environment.
Alongside the home-based scientific work, the team has had some creative side projects, such as experimenting with baking high-fibre knotweed pie.
“It was really delicious,” Merritt reported.
Trinity Western’s summer knotweed study team is led by Dr. David Clements, TWU Professor of Biology and Co-Chair of the Department of Geography and Environment.
Local governments are also battling the plant, including the Township of Langley, which is working to eradicate the invasive species from municipals roads and parks.
The City of Richmond has an Invasive Species Action Plan and the Fraser Valley Invasive Species Society spends more on controlling knotweed than on any other weed.