Getting to grips with Japanese knotweed
I continue to receive many phone calls regarding Japanese knotweed and how to get rid of it.
Japanese knotweed is a very invasive and troublesome weed. It was introduced as an ornamental plant in the 19th century and has spread relentlessly across the island causing ever increasing economic and environmental problems. It can be difficult to eradicate as any small piece of root or any knot on the stem will regrow. The roots can spread nine metres wide and three metres deep.
It is very encouraging to see that more and more local authorities are now actively tackling this scourge of the countryside.
So, how to get rid of it? First of all, what not to do: do NOT try to dig it out, do NOT cut it back and do NOT spray the plants at the wrong time of year.
What will work is to spray the plants with glyphosate at this time of year. That means after flowering but before dieback. If you repeat this for a number of years, you will eventually win the battle.