Invasive Plants

Japanese Knotweed

Japanese Knotweed, Polygonum cuspidatum

Often called bamboo, Japanese knotweed is found across PEI. It is a very invasive plant, native to Asia, that out-competes other plants, creating a monoculture.  This reduction in plant biodiversity reduces wildlife habitat and food, resulting in fewer wildlife species being present.

Japanese knotweed is a non-woody, perennial plant that dies back to the ground each year and can grow up to a height of 3m annually.  It spreads mainly by underground stems (rhizomes).  These rhizomes can grow 60 feet horizontally and 10 feet down.  They cause issues with infrastructure and can even come up through pavement!

At Victoria Park in Charlottetown, we have been experimenting with different ways to manage knotweed patches (cutting the knotweed to deplete the supply of food in its rhizomes, laying down tarps over the knotweed patch and putting soil on top of some of the tarps).  Black tarps created a lot of heat which “cooked” the the shoots but still allowed the plants to grow. The tarp that was covered with the soil created dense shade and prevented and water from getting to the knotweed plants.  There was no green growth under the tarp/soil combination.