The other day whilst surveying birds for the consultancy we came across one of the most invasive non-native plants in the UK. We had already seen it and lots more during the pre-survey recce and habitat survey we completed in December so the owners of the site will find out about it when they receive a report.
What: Japanese Knotweed Fallopia japonica (Houtt.) Ronse Decr.
When: 14th January 2020
Where: a site near Preston Docklands, Lancashire, VC60, UK
Who saw it: My colleague and I
How was it recorded? It will be recorded on the site report.
Is it bigger than a blackbird? Yes
What is it? A species of knotweed that is, as the English name (and scientific name) suggests is native to Japan, and areas of China and Korea too. It was brought to Europe and North America as an ornamental plant where it quickly escaped gardens and became rampant. This species can grow through concrete, so presence in an area can be detrimental to buildings, or potential building works. The root system is particularly strong and the rhyzomes that make new plants are incredibly resilient, surviving in extreme cold and heat and in a variety of soil pH levels. It is therefore incredibly difficult to kill off. I have experience in combating this plant and used pure Glyphosate injected directly into the stem to kill off a patch. This needs to be repeated several times in order to start destabilising the root system below.
A fact I have found out about this species? In the UK all plants are clones of the same female plant (Ref: https://www2.le.ac.uk/departments/genetics/people/bailey/res/f-japonica).
Is it charismatic in my opinion? It’s a pain in the backside, but like many invasives it’s invasive for a reason. It’s ability to thrive pretty much anywhere and be a pain in the backside to us humans must make it charismatic. Or am I giving it too much credit?
A Species a Day 