Japanese Knotweed - How to kill it by Rivers

Very difficult to control. Cutting it down does not work on its own. It will just regrow. In fact the act of cutting it down can help to spread the plant. Just 5mm of Japanese knotweed accidentally dropped into the river can regenerate downstream and cause someone else problems.

Japanese Knotweed is very resiliant. Its roots can run to many meters below ground. Digging it up is not an option.

To kill it:

• First it needs to be weakened by cutting it down during initial growth like any weed. Hit it with a strimmer in April or a bill hook if close to water. Try not to let any bits escape.

• Spray the exposed stumps with a Glyphosate i.e. Roundup.

• Spraying the leaves will have little impact as they reject water unless you mix with a surfactant (washing up liquid will do)

• Do not let the spray hit water.

• Repeat as often as you can untill dead.