A group that combats invasive plants in Ontario wants residents of Thunder Bay to be aware of Japanese knotweed.
The co-ordinator of the Ontario Invasive Plant Council said Japanese knotweed was likely brought to the province as a horticultural plant.
But concern around the plant stems from how it spreads, Hayley Anderson said.
"Once it gets introduced to an area, there's a lag-time of between 20 and 40 years before it actually starts to spread out and become invasive," she said.
"So, even though it may be in very small areas right now in northwestern Ontario, now is the time to control it."
Anderson says the Japanese knotweed isn't common to the northwest, but it does exist in Thunder Bay.
"We are seeing more of it now in Ontario than we ever have before [although] it usually does not do well in areas where there is deep frost," she said.
Where the plant is established, "it can quite quickly become very aggressive and start to take over."
"With climate change, a lot of these invasive species are going to become more prevalent in northwestern Ontario," Anderson added.
"It mostly grows in areas with moist soil, as well as full sun, so it does prefer riverbank areas."
Japanese knotweed mostly spreads by human activity, such as planting it in a garden and moving it. Anderson said people should be cautious about bringing the plant to their camps.