Japanese Knotweed

Fallopia_japonica_MdE_2.jpg

Japanese Knotweed Fallopia japonica

Polygonaceae

Note: Image courtesy of Wikipedia as I can't find my images at the moment. It is the mature plant, so when I find it again, I will replace this with a picture of the immature plant.

Graphic Japanese Knotweed.JPG

Unlike its fellow invasive species, Himalayan Balsam, Japanese Knotweed has no redeeming features. It simply takes over any patch of land where it can find a foothold, establishing a living wasteland. At least, I suppose, it has left the countryside largely unmolested, preferring life in the city. Its main strongholds are London, Edinburgh, Glasgow, Cardiff, Swansea, the West Midlands and, for some reason, the tip of Cornwall, while Dorset, for example, is almost free of the plant.

Being number one in the list of most troublesome invasive species it is universally hated. At least, unlike the triffid, it does not walk about and kill people. Incidentally, the triffid has no Latin name that I can find so I declare it now as Trifida Commiscens sp. nov.. This is a nomen nudum as it refers to something for which there is no specimen.


When mature, the plant is recognised by its pointed, heart-shaped leaves, sprays of small white flowers and signature zig-zag stems which are green and spotted with red. The edible shoots are also distinctive, looking vaguely like asparagus, green with red spots, a cluster of immature leaves at the top which start life pink and pink triangular scales at interval along the stem.


I stick by my low estimation of Japanese Knotweed even though it is edible. The plant is in the Polygonaceae and thus related to dock and sorrel. It is particularly like the latter because it has a fruity flavour. The young shoots are succulent and acidic to the tongue and ‘useful’ in recipes which call for another member of the Polygonaceae, rhubarb. So, Japanese Knotweed is a rhubarb substitute and can be used in crumbles and (a favourite of foragers keen to demonstrate their hedge-cred) a vodka/rum/gin/brandy infusion. The stems are a little fibrous, even when cooked, so on the rare occasions I find the plants, I cook it and sieve out  the puree. Generally, however, I don’t bother, as I have a very fine rhubarb plant at the end of the garden that could give Trifida commiscens a run for it money any day