Wild Edible: Japanese Knotweed

Posted June 27, 2016 by Lauren Dibble in Gardening, Recipes / 4 Comments

japanese knotweed

japanese knotweed

An invasive species to the US, Japanese Knotweed is native to Japan, China and Korea. It was brought to Europe and the US as a decorative landscaping element.

 Identification

The stems grow up to 10 ft in height, are hollow, and have nodules every so many inches, resembling bamboo.

The flowers are a small, cream or white, produced in erect racemes a3-6 inches long in late summer early autumn.

Other names include fleeceflower, Himalayan fleece vine, monkeyweed, monkey fungus, Hancock’s curse, elephant ears, pea shooters, donkey rhubarb, sally rhubarb, Japanese bamboo, American bamboo, and Mexican bamboo (although it is neither a rhubarb or bamboo).

In chinese medicine it is known as Huzhang which translates to tiger stick.

It is listed as one of the world’s worst invasive species. The root system is large and strong enough to break through concrete sidewalks or foundations. You’ll frequently see it on roadsides, construction sites, or any place the ground has been turned up. It will grow in such a dense colony that it will crowd out any other plant. It is so prolific, any part of the plant can grow new roots, so be very cautious when harvesting this plant to not drop any part of the plant on your way home. I would not recommend putting this in your compost bin. In fact, in the UK, landfills have to be licensed to handle Japanese Knotweed.

Uses

Japanese knotweed is highly valued by beekeepers, as the flowers provide a source of nectar when little else is flowering.
For eating the stalks, harvest the young shoots under 10 inches in height. They can be steamed directly as with other vegetables, simmered in soups, or baked in dessert dishes.
For eating the leaves, the Cherokee used to harvest and cook them before eating.

Nutrition

Japanese Knotweed is an excellent source of vitamin A, vitamin C, and the antioxidant flavonoid rutin. It also provides potassium, phosphorus, zinc and manganese. It also contains the same resveratrol in red wine that lowers bad cholesterol, but in higher quantities!

Medicinal Uses

Eating large quantities of Japanese Knotweed will act as a gentle laxative, like rhubarb. It is also said to be very effective when used to treat and prevent lyme’s disease. It  contains anti-inflammatory properties that helps treat Lyme’s and arthritis symptoms.

Control

To eradicate Japanese Knotweed on your own property with herbacides, you have to dig up every inch of roots, which can grow up to 10 ft deep. I recommend digging up at least 11 ft around the plant and roots, and burning the soil.

Japanese Knotweed Purée

Gather stalks, choosing those with thick stems. Wash well and remove all leaves and tips. Slice stems into 1-inch pieces, put into a pot and add ¾ cup sugar for every 5 cups of stems. Let stand 20 minutes to extract juices. Add only enough water to keep from scorching, about half a cup. Cook until pieces are soft, adding more water if necessary. They will cook quickly. When done, the Japanese Knotweed needs only to be mixed with a spoon. Add lemon juice to taste and more sugar if desired. Serve chilled for dessert just as it is, or pass a bowl of whipped cream. This purée is excellent spooned over vanilla ice cream or baked in a pie shell. Keeps well in the refrigerator and may be frozen for later use.

Japanese Knotweed Jelly

makes 6- 8oz. jars

4 c. water
8 c. chopped Japanese knotweed stalks, leaves removed
1. Add the water and the chopped knotweed stalks to a large pot. Bring the water up to a boil, and reduce to a simmer for 10 minutes. Allow the mixture to cool, then hang the stewed knotweed in a jelly bag or in cheesecloth, and allow it to drip for an hour or two. You need to end up with 3 1/4 c. knotweed juice.
3 1/4 c. knotweed juice
1/4 c. lemon juice
1 box Sure-Jell powdered pectin (1.75 oz.)
4 c. sugar
2. Put the knotweed juice, lemon juice, and pectin into a large pot. Bring it up to a rolling boil.
3. Add all the sugar at once. Bring it back up to a rolling boil, and boil 1 minute while stirring constantly.
4. Remove from the heat and ladle it into hot, sterilized jars, cover. Process in a water bath for 10 minutes

Japanese Knotweed Muffins

makes 8 muffins

1/2 c. sugar
2 c. chopped Japanese knotweed stalks
1/4 c. water
1 Tbsp lemon juice
1/4 c. oil
1 egg
1 c. flour
1/2 c. sugar
1/2 tsp baking powder
1/4 tsp baking soda
1/4 tsp cinnamon
1. Preheat the oven to 325°, place baking papers in a muffin pan.
2. In a saucepot, combine 1/2 c. sugar, the chopped knotweed stalks, 1/4 c. water and 1 Tbsp lemon juice. Cook over medium heat for 10 minutes, stirring often. Allow the stewed knotweed to cool. There should be about 1 c. stewed knotweed.
3. In a large bowl, whisk the egg with the oil, and stir in the stewed knotweed.
4. Sift together 1 c. flour, 1/2 c. sugar, baking powder, baking soda, and cinnamon. Stir into the wet ingredients in the large bowl, do not over mix.
5. Fill the muffin papers about 3/4 full. Bake for 24-28 minutes, until the top is set and springs back when touched. Cool and serve with butter, or toasted.

Japanese Knotweed Summer Rolls

makes 6-8 rolls

6-10 8″ Vietnamese rice paper wrappers
3 oz. bean thread noodle cakes
1 c. thinly sliced Japanese knotweed shoot stems
1/2 c. chickweed greens, or parsley and cilantro leaves
3 Tbsp dandelion flower petals
2 Tbsp chopped ramps leaves, or chopped scallions
4 Tbsp shredded carrots
Thai dipping sauce
1. Soak the bean thread noodles in hot water for 10 minutes, until they soften. Rinse and drain well.
2. In a bowl, add the chopped knotweed, chickweed greens, dandelion petals, ramps, and carrots to the bean thread noodles. Toss well.
3. Soften the rice paper wrappers in warm water for about 15 seconds until they are pliable. Place on a smooth surface.
4. Take about 1/2 cup of the noodle filling and place it in the center of the top third of the wrapper. Fold over the top of the wrapper to cover the filling, then fold in the two sided toward the center. Now roll the filled wrapper towards the bottom, enclosing the filling completely. This may take some practice!
5. Chill the summer rolls for 15 minutes, and serve with a spicy-sweet Thai dipping sauce.

Japanese Knotweed Jelly

makes 6- 8oz. jars
4 c. water
8 c. chopped Japanese knotweed stalks, leaves removed
3 1/4 c. knotweed juice
1/4 c. lemon juice
1 box Sure-Jell powdered pectin (1.75 oz.)
4 c. sugar
1. Add the water and the chopped knotweed stalks to a large pot. Bring the water up to a boil, and reduce to a simmer for 10 minutes. Allow the mixture to cool, then hang the stewed knotweed in a jelly bag or in cheesecloth, and allow it to drip for an hour or two. You need to end up with 3 1/4 c. knotweed juice.
2. Put the knotweed juice, lemon juice, and pectin into a large pot. Bring it up to a rolling boil.
3. Add all the sugar at once. Bring it back up to a rolling boil, and boil 1 minute while stirring constantly.
4. Remove from the heat and ladle it into hot, sterilized jars, cover. Process in a water bath for 10 minutes, cool.

4 responses to “Wild Edible: Japanese Knotweed

  1. Nora

    I stopped reading after the article stated it was native to Japan, China and Korea but brought to USA as landscaping…. then latter the article said ” the Cherokee harvested and cooked them “

    • Nora – Japanese Knotweed was introduced in the late 1800’s on the East Coast of the US. The Cherokee nation was still strong on the East Coast up until around 1930’s when their government was relocated to Oklahoma.

  2. I’ve been trying to eradicate this from my yard since we bought our house five years ago. So I was intriguted to read your article on ways to use this very invasive plant. Thanks!

    • Lauren Dibble

      Happy to help! Getting rid of it can be a HUGE pain, but if you can’t get rid of it, you may as well eat it!

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