Japanese Knotweed

The Problem

JKW can cause significant damage to construction work and has the power to grow through tarmac, paving stones, brickwork and cement. If left untouched JKW will out compete and smother are native species. The plant’s leaf canopy of broad leaves obstructs light to the ground preventing natural flora and fauna from growing. Dead vegetation decomposes slowly over a number of years and also obstructs light. It also creates a fire risk during the Summer months and during dry periods. The plant can survive extreme heat and is found in volcanic areas within its natural habitat so burning JKW will not eradicate it. All it takes is is a piece of rhizome less then 0.7g to grow a new plant.

  • Spring Growth

  • Summer

  • Winter

  • Flower

  • Leaves

  • Stems

  • Rhizome

Legislation: Law & Acts

Japanese knotweed is governed by numerous laws and acts concerning the way in which it is treated and disposed of, due to its damaging ability to spread aggressively if mishandled.

The Wildlife Order (NI) 1985

In Northern Ireland The Wildlife Order (NI) 1985 (as amended) states that it is an offence under Article 15 if anyone plants or otherwise causes to grow in the wild any species of plant listed on Schedule 9 Part II.


Greentown offer all treatment plans and also an insurance backed supervisory service when required.

To find out more on other Invasive and Noxious weeds click here