Japanese Knotweed grows quickly but will usually take the path of least resistance – the easiest path to allow for maximum growth. Research shows that Japanese Knotweed can and will damage property, walls, fencing and drainage by exploiting any existing weakness in the structure. The plant is capable of making a small weakness far worse as it grows and expands so what was a small crack becomes larger and more problematic.
Japanese Knotweed can cause damage, but the risk is real so it is always better to act quickly and remove the risk before these problems occur.