Japanese knotweed can seriously damage buildings, hard surfaces and infrastructure. The underground structure of rhizomes slowly expand, exploiting any cracks or voids. Once established, it can be very hard to control and will exacerbate any existing weakness in structures, such as drains or patios. Its presence on development land causes economic loss to the construction sector, primarily through the cost of control and eradication.

Japanese Knotweed has vigorously invaded the natural environment and outcompeted our native plants. It forms thick, dense stands that cast shade on the area below, limiting the growth of other species and seriously reducing local biodiversity. These thick stands can reduce the capacity of channels to carry flood water, causing upstream flooding. In winter, the stands die back, exposing the river bank to erosion.

Its presence on domestic properties can result in the refusal to provide a mortgage, impeding or preventing property sales and reducing property values. It can also lead to neighbourly disputes and even legal costs.