Wild and Weedy Wednesday: Bohemian Knotweed

I am sure many of you have heard of Japanese Knotweed, a huge plant that is considered one of the worst invasive species worldwide, growing up to 30cm a day and spreading by rhizomes deep in the soil.

Well, we have something similar in our garden: Bohemian Knotweed. Reynoutria x bohemica.

 It is in fact a cross between Japanese Knotweed and Giant Knotweed. The leaves are much larger – up to 30cm – and a kind of elongated heart shape. It can grow to over three metres tall and the stems are extremely tough and hollow, resembling young bamboo shoots.

It is actually a very attractive plant, and I expect that was why Japanese Knotweed was introduced to parks and gardens as an ornamental plant in the west in the 19th century – before they realized how rapidly it spread.

Not only does it have beautiful foliage, the white flowers which open in August also look quite majestic the way they stand upright. (And in autumn the leaves often turn a lovely burnt orange colour.)

Bohemian Knotweed is supposedly even more invasive than its parents, but we have been able to confine it by cutting it down or mowing over it in the two or three areas where it has always grown. It is extremely resilient to all growing conditions and can even grow through concrete! The roots can be up to 3 metres deep and extend up to 7 metres horizontally, so it is almost impossible to remove without using chemicals.

Apparently it is edible: the young shoots are said to taste like rhubarb. Wikipedia says:

Young leaves and shoots, which look like asparagus, are used. They are extremely sour; the fibrous outer skin must be peeled, soaked in water for half a day raw or after parboiling, before being cooked.

I will not be trying it. It also contains valuable Resveratrol, which in herbal medicine is said to reduce inflammation.

I was worried at first when we found it growing within our fence, but it has not posed a problem so far, so hopefully it will remain that way.

Have you had any experience with aggressive knotweeds?

Thanks for visiting. Until next Wednesday,

Happy Weeding!