What Is Japanese Knotweed?

Make no mistake: Japanese Knotweed, or Fallopia Japonica, a rhizomatous perennial plant, is a ferocious creature. Native to Japan, Korea and parts of east Asia and China, where the extent of its growth is combated by fungus and insects, Japanese Knotweed does not present the same problem is does in the western world, thousands of miles from its natural habitat.

Introduced into Europe in the 19th century as an ornamental plant, as well to provide ground cover and fodder, it’s brought untold worry and turmoil to grounds everywhere ever since. So why is it so destructive?

In Victorian Britain, travelling the globe was popular amongst the upper classes. Botany; the study and collecting of plants was also very popular in this age of science and reason, meaning many exotic species found their way on to British soil. The gardens of the aristocracy were crammed with prizes from their travels, and should a species fail to thrive or simply go out of vogue, they would be dug up and discarded. And Japanese Knotweed was one such plant.

Dumped in disused quarries, waterways or anywhere conveniently out of sight, Japanese Knotweed thrived. Tiny fragments of stem, or rhizome can easily take root and regrow in to new plants, and the original root system would regrow just as quickly. Getting rid of Japanese knotweed is easier said than done, especially since each years its regrowth would be chopped and dumped, exacerbating its spread, year on year.

It is only in recent decades the full extent of this relentless fly tipping of a plant which seemingly refuses to die has been realised, and as a result, the transportation and disposal of Japanese Knotweed stems, roots and contaminated soil is strictly controlled.

As Japanese Knotweed contractors and consultants we are here to help anywhere in the UK.

Identification

The different seasons bring out a wide variety of characteristics of Japanese Knotweed. Below the different images and descriptions below should give you a better insight on how to identify Japanese knotweed and allow you to identify whether or not you have an issue. But if in doubt please email us a range of photos and we will be able to assist you.

Spring

  • The first signs of Japanese Knotweed growth, Usually there is early signs of growth are seen in mid-March
  • Distinctive red and purple shoots – often accompanied by rolled back leaves which grow rapidly from the stored nutrients in the rhizome.

Summer

  • The stem resembles bamboo, though more green in colour with purple speckles.
  • Inside the cane it has distinctive chambers that retain water and nutrients.
  • The leaves are large and have pointed tips that extend from the stem in a zig-zag pattern.
  • Later in the season creamy-white flowers hang in clusters from the stalks.

Autumn

Winter

  • As the first frost appears the plant’s leaves turn brown, and the plant withdraws back into its rhizome.
  • The canes lose their colour and turn into woody stalks which can take years to decompose.
  • New shoots can be found growing through the dead canes in the early Spring.

DIY Japanese knotweed eradication

The different seasons bring out a wide variety of characteristics of Japanese Knotweed. Below the different images and descriptions below should give you a better insight on how to identify Japanese knotweed and allow you to identify whether or not you have an issue. But if in doubt please email us a range of photos and we will be able to assist you.