Foraging: Identifying & Eating Japanese Knotweed

So spring is officially sprung up all around us, and I am back on the blog. I really didn't do much last year, but I am determined to make at least one post a week this year, and see where it goes.

If you are looking to start foraging, April is a great time to get into it. There are tons of really tasty edibles flourishing right now, and they are easy to find and identify. Bonus, its just a great time to be outside enjoying nature!

Identification difficulty: Beginner

Stand of knotweed at the perfect stage for harvesting.
Note the dried stalk's from last year's plants in the back and on the ground. 

Where to find Japanese Knotweed

The husks of last season's plants can be spotted at a distance 

As another invasive species, knotweed can be found anywhere -- it can even come up through concrete! But  it prefers to grow in disturbed ground near the water, so you can mostly find it on the banks of creeks and rivers, where the spring floods wash competition away, and the knotweed--with roots up to 10 feet deep--can grow and spread uncontrolled. You can best find it by looking for the husks of last year's plants. If still standing, they can be up to 6 feet high, and if they have fallen, they have likely covered the ground with long, reed-like tubes. These tubes are hollow, and feature bamboo-like joints. Because they grow so densely, allowing no competition, you can frequently see unbroken beds of knotweed from quite a distance.



Identification

Key identification features:
jointed, red-spotted stems & reddish leaf tones

Once you have found a patch of last-year's dead plants, look for the young shoots of this year's growth. Though it is possible to find knotweed without last years remains, I would probably avoid any such plants I found as a new forager. The dried out husks provide a helpful identification feature. Young spring knotweed, which is what you want to harvest, resembles a bamboo/asparagus hybrid. The stalks are juicy, and become hollow very quickly. They have red spots, and red bands around the joints--the joints which resemble those of bamboo. The triangular, or spade-shaped leaves are red/purple when very young, and then become dark green, with reddish/purplish tones.

Harvesting & Sustainability

Knock yourself out. You can't kill this stuff, governments spend BILLIONS annually trying to do just that. Only harvest the plants in the mid-spring (in the northeast from early April to early May), when they are still easy to break off. As they get older, they get stringy just under the skin, and may require peeling. After they get woody, and can no longer be broken off, they also become inedible. As with garlic mustard, never take any part of the root (to avoid accidental planting), but in the case of knotweed it's even worse: make sure to boil or burn any clipping you don't use, as the plant can apparently root from even the smallest piece.

Preparation & Taste
Remove any fully fledged leaves, and petioles (leaf stems). You can remove the bunched leaves at the end of the stalk or you can eat them, but the texture doesn't appeal to everyone. Knotweed can be eaten raw, in salads, or as a snack; it can be pickled, or cooked in anyway that asparagus would be cooked (steamed, roasted, stir-fried, sauteed, etc). It is also frequently used as a rhubarb substitute in baked or cooked dishes. Stay tuned as I have been experimenting with knotweed, and will have some recipes up soon. Many people say knotweed tastes like rhubarb, and maybe they are right--I have never had rhubarb. I think it tastes like lemony celery, with an acidic tartness and a celery-like texture. I don't bake much, so I use it as a vegetable.

Special Warning
Knotweed contains oxalic acid, (as does sorrel and other cultivated vegetables) and should be avoided by those with kidney problems.