What is it ?
Japanese knotweed is an aggressive semi-woody perennial plant that is native to eastern Asia. In the 1800’s it was introduced to North America as an ornamental species and also planted for erosion control. It has since spread throughout the United States and Canada.
Growing up to 6.5 feet tall and 65 feet wide this bamboo like species spreads quickly and through its underground system can undermine the structural integrity of buildings. It forces its way up through every crack imaginable, in patios, concrete paths and even in walls and floors. Which is BAD news for your home. What's more, getting rid of it is a task beyond the average gardener. It can take up to five to ten years of regular chemical blitzing before the knotweed all clear can be sounded!
How do I know if I've got it?
Fleshy red tinged shoots when it first breaks through the ground
Large, heart or spade-shaped green leaves
Leaves arranged in a zig-zag pattern along the stem
A hollow stem, like bamboo
Dense clumps that can be several meters deep
Clusters of cream flowers towards the end of July that attract bees
Dies back between September and November, leaving brown stems