Japanese knotweed (Fallopia japonica) is one of the most invasive weeds in the world.  Native to Asia, It was introduced to the United States in the late 1800s as an ornamental plant.  Although its delicate flowers are attractive when in bloom, they are rather too small to elicit much praise for their aesthetics today.  It was also originally touted as being useful for stabilizing eroding roadsides and creating windbreaks due to its rapid growth habit.  Japanese knotweed produces thousands of seeds per plant and can also spread vegetatively underground. This aggressive development, while originally one of the plant’s attractive qualities, is what has led to its current invasive status today.  Where it has established, large stands of this plant can outcompete native species, with individual Japanese knotweed plants growing up to 10 feet high, at a rate of up to 3 feet per month.  It is commonly found along road sides, woodland edges and river banks.  In fact, if you look, you can probably notice clusters of Japanese knotweed stems sprouting along the side of the road while you’re driving.

While you could simply do your part to eradicate this plant by cutting it down and disposing of the debris or applying pesticides, another way to tackle the plant is to eat it.  Although the plants can grow quite tall, the best time to harvest Japanese knotweed for food is during the mid- to late-spring, before the plant has grown higher than a few feet tall.  At this stage, knotweed looks like fat, green, red-flecked vertical stalks poking up from the ground that are still unbranched.  To test whether the plant is still tender, bend the stalk.  The tender portion of the knotweed stem should snap right off, making a satisfying popping noise.  Once the plant matures, the stalks get tough and less palatable.  Although it is not necessary to remove the small leaves at the tip of the stalk, any larger developed leaves growing from the nodes should be removed.

We collected a bag full of Japanese knotweed stalks in a matter of minutes from a riverside area in Wareham.  Raw, it has a sweetly tart taste, and a slightly crunchy texture.  Although we had no immediate culinary use for the stalks we picked, Japanese knotweed freezes well, and can be thawed later for use as a rhubarb substitute in pies and jams, or sliced and eaten as a crunchy vegetable in stir-fries. It is easier to work with in the future if you peal and chop it before freezing.