Japanese knotweed (Polygonum cuspidatum or Fallopia japonica) is often labelled as an aggressive alien invader since it is difficult to eradicate once established. It prefers disturbed areas, roadsides, banks of streams, and edges of dirt roads and fields. One way people try to remove knotweed is with herbicides and poison, so avoid limp, brown stalks with dead leaves near roadways and trails. A good place to search for some is along the trail at the Thompson Dam in Connecticut, where we also have two Japanese Knotweedletterboxes (and a bonus!) hidden.
Knotweed grows in dense patches, up to 6 feet high by summer's end. It is the shoots we look for in early spring, picked before they are 12" tall, otherwise they become stringy and woody. The stalks are jointed and hollow, and the leaves are a rounded triangle shape, with a straight base. The plant produces sprays of white flowers late in summer, and winged seeds that spread on the wind easily. Knotweed is a perennial, so a patch will always return to the same place every year. The taste of the green flesh is a cross between rhubarb and a green apple, tart and lip puckering. Gillian loves to chomp on these right on the trail, raw.
The flavor and texture is so similar to rhubarb, we use it in recipes like chopped rhubarb. We have made coffee cakes, shortbread bars, tea breads and pie with Japanese knotweed. We also made a small batch of wine last year, which came out very dry, with a vegetal finish. I have a rhubarb cookbook that I skim for ideas, and this tapioca turned out very nicely, gobbled up by Gillian and Robert. Click here for a short video of Russ Cohen talking about Japanese knotweed. We have some more recipes for Knotweed Jelly, Cold Knotweed Soup, Knotweed Wine, and Knotweed Dessert Bars.
Japanese Knotweed Tapioca Pudding
3 T. quick cooking tapioca
1 c. sugar
1/4 tsp salt
1 c. water
2 c. chopped Japanese knotweed stalks
1. Place all ingredients in a saucepan and let sit 5 minutes.
2. Bring to a boil and cook 2 minutes over medium heat, stirring constantly.
3. Chill. Serve with a squirt of lemon or lime juice.