Invasive Wild Edibles: Japanese Knotweed

This large, fast growing plant may be a problem for American ecosystems, but it is pretty delicious too. Given its not-so-popular status, nobody will complain if you are cutting it up and pulling it away for your salad, and the reward is a tasty treat that is in abundance throughout most of the country.

Japanese Knotweed as an Invasive Species

Japanese knotweed is notorious because of its success. Taking over wetlands, roadsides, drainage ditches and other sunny areas, it grows into a thick mat of bamboo like stems, crowding out other plants and out-competing native species. It can handle a diversity of soils, temperatures, and salinities, and it produces large, protruding rhizomes that make removal difficult. It typically requires multiple bouts of herbicide to kill, and it resists cutting or excavation by sprouting from roots or rhizomes.

All these facts turn the Japanese knotweed plant into a real enemy of the native plants, especially in the eastern United States. It easily displaces native plants, and with the exception of honeybees, it doesn’t really help anyone along. At least, it would be a problem if knotweed didn’t have such an easy use in the kitchen.

Identify knotweed by the bamboo like stalks stretching typically less than 2 meters up. It grows in clusters of clones, and the leaves are broad. It flowers in late summer with upright, white clusters.

Eating Knotweed

Knotweed is actually quite delicious in the kitchen. Like most wild edibles, the flavor is unique to the plant, but is best compared with a rhubarb stem. It has an acidic, slightly citrus flavor as well, but no single comparison will do. Thankfully, it is mild enough in any and all flavors to be a versatile addition to your cooking.

Most recipes use the young plant parts, before they have become woody. Early shoot harvesting helps slow down the spread and gives you an easy meal. Tips of stalks are also edible and palatable as well. In fact, it also is a great source of resveratrol, the supposedly healthy ingredient in red wine.

In my cooking, I like to steam or saut© the knotweed tips. They can work in savory and sweet dishes by changing whether you cook them in sugared water or olive oil. The texture of the shoots is much like asparagus, so cut it small or cook it until quite tender.

Warnings on Japanese Knotweed

There are a few warnings with Japanese Knotweed that should be considered. First, don’t eat knotweed growing in industrial runoff. In fact, don’t eat anything that lives in factory runoff. Second, don’t eat knotweed that was sprayed with herbicide. Most people use glyphosate for this, which should be “safe enough”, but why risk it when there is plenty of knotweed in the area to eat. Finally, knotweed contains oxalic acid, just like rhubarb. It discourages grazers, and it should discourage you too if you suffer from joint diseases or hyperacidity. Avoid mature stalks especially, since they have a greater concentration of the acid.

Japanese knotweed is a great renewable herb to add to your diet. It is free, tasty, and easy to identify. It is an easy plant to get started on (in moderation, health permitting) and is fun to harvest as well.


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