Japanese Knotweed Cooking and Recipes

Strawberry-Knotweed Bavarian

The flavor of Japanese knotweed is often compared to rhubarb or tart green apples, but it also has an earthy, green flavor as well. In our experiences, people either really like it or really dislike it based on the preparation. We tend to use it in sweeter recipes like cakes, jelly, or syrups, but we also use it in savory recipes like pickles, grilled with a miso marinade, or raw in a summer roll.

Knotweed sliced thinly and eaten raw in summer rolls

Japanese knotweed is a really invasive perennial plant that spreads through aggressive underground rhizomes. It looks similar to bamboo because it has a hollow stem and joints that form cross walls inside the stem, but knotweed is not related to true bamboo. The shoots emerge looking a bit like asparagus before the leaves start to unfurl, and will be green but deeply mottled or spotted with red. It can grow up to 12 feet tall or more, and will have multiple branches along the main stalk. The leaves of different species can appear slightly different; some are shaped like an elongated heart, while others are shaped like the blade of a shovel with a straight back edge. In the late summer, pretty sprays of white flowers emerge, a great source of food for bees. Once pollinated, knotweed produces winged seeds that may persist through the winter. The dried stalks will also last through the winter and it is one of the easiest ways of finding a patch of shoots by looking for the skeletons of last year's knotweed.

Sweet banana bread with Japanese knotweed added

The season to harvest Japanese knotweed shoots in southern New England typically lasts about two weeks when the shoots are less than 10"-12" tall. Once the shoots start to branch out and the leaves have all unfurled, the stem becomes quite tough and woody--not suitable as food. When the knotweed in the southern portion of Connecticut gets too tall, we can start driving north to find shorter shoots to collect and cook. Knotweed doesn't freeze well when raw, but can be dehydrated to make a tart infusion to drink, or can be stewed with sugar and frozen in measured portions for later use in recipes. It can also be salted and preserved but will need to be rinsed and soaked to use in recipes. Flavored syrup and jelly made from knotweed will last all year until spring comes around again to start cooking with fresh knotweed.

Knotweed jelly

Besides using Japanese knotweed shoots as food, the rhizomes are used medicinally as they are high in resveratrol. Knotweed may also be useful in treating Lyme disease by fighting off the Lyme spirochetes and providing anti-inflammatory support for the body. We even use the older, dry parts of knotweed to make biodegradable straws or for use as chopsticks when hiking or camping and we forgot utensils. As kids know, the hollow segments of the dried knotweed stalks also make excellent blowguns, but don't tell mom I showed them!

Knotweed muffins

To find many of our Japanese knotweed recipes click HERE.

Raw Japanese knotweed in a spicy coconut-red curry sauce

When very tender, knotweed can be eaten like a crunchy vegetable

Knotweed syrup