Japanese Knotweed

Japanese Knotweed

Wetherell, 2009

Plaguing Vermont and many other states in the eastern US this herbaceous perennial poses a significant threat to natural areas at a large scale, particularly riparian sites where Japanese Knotweed is able to tolerate extreme flood events. Flooding events which this species have shown great capacity to withstand will increase the competitive advantage for this species with the overlay of global climate change and the predicted increase in severe weather events. 

Japanese Knotweed, capable of growing over ten feet in height, was introduced in the United States, in the late 1800s, as an ornamental plant and subsequently was used as an erosion control mechanism and in landscaping projects. Once established, Japanese Knotweed has proven itself as an extremely persistent species. Several years ago it was placed on a list generated by the National Parks Service, “Least Wanted Invasives” (Remaley, 2009)

At present herbicide use is the primary mechanism for controlling this species but if the public was more aware of the culinary uses for this species maybe harvesting could become the primary means of eradiating these species, or at least ceasing the spread.

Japanese Knotweed is an excellent source of vitamin A, vitamin C, and the antioxidants, in addition to providing potassium, phosphorus, zinc, and manganese. Another benefit that comes from eating the plant is the chemical resveratrol. Resveratrol can also be found in the skin of grapes and in red wine, and it works to lower cholesterol and reduce the risk of heart attacks. Studies have also been done that show that resveratrol may delay the onset of Alzheimer's disease or slow its progression (Brill, 2008).

In culinary terms Japanese Knotweed is not quite as versatile as garlic mustard, another commonly found invasive species in Vermont, that being said, a lot can still be created using the plant and it can still become a kitchen classic for your family if you learn to love the recipes that include it.

 The shoots of the plant are most commonly be used for cooking, and should be harvested when they are between 6 to 8 inches tall in order to achieve the best flavor. They are intensely tart and tangy and have a taste similar to rhubarb, and some claim better (Brill, 2008).

The taller shoots also can be used; the tough rind that covers them can be exploited to make marmalade.

The stems have a variety of uses. They can be steam as a vegetable, and simmer in soups.  Sauces, jams, and fruit compotes are additional options.  People who have experimented with cooking Japanese Knotweed have forewarned of using it sparingly, the taste is extremely powerful if overdone (Cohen, Sanctuary Magazine: Eat Your Invasives , 2011).

Recipes that include Japanese Knotweed can be found below. 

By: Sabrina Smits 

Bibliography 

Brill, S. (2008). Japanese Knotweed . Shoots and Greens of Early Spring in Northeast North America . New York : http://www.wildmanstevebrill.com/Plants.Folder/Knotweed.html.

Cohen, R. (2008 , September 5). Janpanese Knotwood Recipes . New England Wild Flower Society . http://www.newfs.org/protect/invasive-plants/specific-invasive-plants/japanese-knotweed-recipes.html/.

Cohen, R. (2011, March 15). Sanctuary Magazine: Eat Your Invasives . Mass Audubon . http://www.massaudubon.org/sanctuary/features.php?id=94.

Remaley, T. (2009, December 10). Japanese Knotweed . Plant Conservation Alliance's Alien Plant Working Group: Least Wanted . http://www.nps.gov/plants/alien/fact/faja1.htm.

Wetherell, S. (2009, May http://www.foodista.com/blog/2009/05/29/japanese-knotweed-apple-crumble). Japanese Knotweed .