Invasive plants? Correct identification is essential!

Here’s a thought for all the CSJK surveyors out there… you are carrying out a routine Japanese knotweed survey for your client. None found so you submit a negative report, and you’re pretty sure you would have spotted any Giant hogweed or Himalayan balsam if it was present. Client happy. But what happens when they find later that the site is infested with Monbretia (Crocosmia) and those woody shrubs you weren’t sure about turn out to be Japanese Rose (Rosa japonica) or Black locust (Robinia psuedoacacia)?

Do you know your terrestrial species?

All are listed under Schedule 9 of Section 14 the Wildlife and Countryside Act 1981 (Robinia – only in Scotland) so could be a significant liability to a property developer or even just a residential client! You might not be ‘liable’ assuming you defined the scope of your survey but you would definitely want to avoid this scenario!

Can you ‘spot’ the key characteristics?

How likely is this scenario? Probably more than you’d like to think. After all, apart from the knotweeds and the species mentioned earlier, there are another 40 terrestrial plants on one list or another of ‘alien’ plants (the EU’s preferred terminology) and 18 aquatic species too. It’s a tough ask to recognise them all, especially as many are still (thankfully) quite rare. But we do think it is worth setting yourself the challenge of being able to ‘spot’ the key characteristics of all those that are likely to be present in your area or on specific sites (geography, soil chemistry etc., can all be factors).

New course for invasive plant identification

Indeed, many of our members have lobbied for help in this area and we are looking forward to launching our new course, “Invasive Plant Identification” on 1st August – which will be presented by Laura Jones M.Sc. who gave an excellent presentation at last years’ International Invasive Weed Conference on this very subject. This course will focus on about 15 terrestrial species and highlight the need to recognise not just the adult plants, but seedling stages too – not to mention overwintering. The plants have been curated in our very own greenhouse, following significant investment from the PCA to ensure we are able to demonstrate the varying traits of these species – just like Japanese knotweed, all these plants have different characteristics throughout the year!

Interested in finding out more?

If you would like more information on the course, please get in touch with our training team on Even if you are unable to make the 1st August, we would love to hear from you and keep you abreast of new dates as and when they are confirmed.

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