Japanese Knotweed originates from Asia and, testament to its ability to survive in extremely harsh conditions, is the first plant to recolonise volcanic areas. It is now found in approximately 90% of the UK.
In the UK, we only have the female plant and so it relies on its root system (rhizome) to spread. This is significant because just 0.7g of rhizome material is all it takes to start a new plant and the rhizome material is viable all year round. During summer months, broken pieces of the above ground material will also cause Japanese Knotweed to spread.