Japanese Knotweed Reporting Form

This form is for reporting the location of invasive Japanese Knotweed (Fallopia japonica). Please supply the species, date, and location. Please also include a photo if possible. You can use the map to get the UK grid reference of your sighting or you can manually add the geographical position. Please add any details you think relevant in the notes section of the form.

Disclaimer: We do not provide any removal or reporting services for Japanese Knotweed. Please note that it is not illegal for Japanese Knotweed to be present on a property, only for it to be allowed to spread. For more information on Japanese Knotweed, visit the Devon Local Nature Partnership.


Identifying Japanese Knotweed

Japanese knotweed was introduced to the UK from Japan in the 19th century as a garden plant, but has since become established in the wild, rampaging across roadside verges, riverbanks and waste ground. It is a fast-growing, invasive weed, which prevents other native species from growing, and is often used to highlight the issues of introducing alien species.

Identifying Characteristics:

  • Triangular or “spade shaped” leaves
  • Hollow stems or canes, distinctive purple speckles reaching up to 2-3m tall in summer. These become brown during autumn and winter.
  • Elongated clusters of creamy white flowers that grow to around 0.5cm wide and 10cm long. Present August – September.

We have a selection of photos to help with identifying Knotweed below. Use the buttons beneath the images to scroll through them. The submission form for records can be found at the bottom of the page.

Japanese Knotweed Flowers. Image courtesy of Hazel Reading.

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Uploading Images

Nowadays, nearly all smartphones have high-resolution cameras. The pictures taken by these cameras can be extremely large, and this can become a problem when you start to share your images to online applications, requiring increased bandwidth and storage. If you are able to compress or resize your images, you will be able to send more as there is an maximum upload of 25mb. There are a number of apps for Android and IOS that allow you to resize images before you upload them here. Please wait for the bar to completely fill on the image uploader before sending.

Using the map

  • Left-click and hold to drag the map left and right, up and down.
  • Use the plus and minus buttons on the left side of the map to zoom in and out.
  • Use the above actions to find the location on the map you are interested in.
  • Left-click on the map to drop a marker at your required location and populate the form grid-ref, latitude and longitude boxes with the correct values.
  • You can reposition with a left-click and hold, dragging the marker to a new position. The grid-ref , longitude and latitude are re-calculated.

Submission Form

    Add up to five photos to help us verify your sighting. Total image size must be less than 25mb.

    Confirm that you are willing for records and your contact details to be passed to the relevant county recorder