Japanese knotweed blog

How can you tell if there’s Japanese knotweed?

I am often asked, can you tell if there is Japanese knotweed in the back garden?  This one such example.  The garden is very overgrown with brambles.  If there was a mature Japanese knotweed plant then I would expect it to be growing through the brambles and taking over the garden; however if there is a small young shoot here, it would be very difficult to identify as it would be under the bramble canopy.  So having a look in your neighbour’s garden (if thats possible!) to see if there is any Japanese knotweed is often a good indication for yours – that is if you’ve not been out in the garden this summer and its a bit over grown like this one!

Large Infestations of Japanese Knotweed

Treating large infestations of Japanese knotweed does take time. Using stem injections six months later can have some good initial effect, but still requires long term monitoring.  (Yes for those keen eyes there is more Japanese knotweed in the background of the second photo! At this visit requested not to treat it, which is why monitoring is also so important to control the activity of the plant.)

What to do when you find Japanese knotweed

PCA’s Technical Manager for Invasive Weeds Peter Fitzsimons, spoke on the BBC Radio Ulster – On Your Behalf programme about Japanese Knotweed. The programme discusses ‘the issues with Japanese Knotweed, what to do and what not to do when you find it on your propertyTo listen please click the link, the article is 27 minutes in: https://www.bbc.co.uk/programmes/m00003t3

How to identify Japanese knotweed

If you’re concerned a fast growing plant in your garden may be Japanese knotweed, here’s what to look out for:

Bamboo like stems, which are green with purple speckles

Zig-zag stems with flat leaves, heart shaped at the very tip

Roots that snap like a carrot, with an orange circle to them