Wild Edible: Japanese Knotweed

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 For Japanese Knotweed

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! In fact, it has the highest concentration of resveratrol of any known plant.

Medicinal Uses of Japanese Knotweed

There are over 67 compounds in Japanese Knotweed that have been identified for medicinal properties, including stilbenes, quinones, flavonoids, emodin and polydatin.

Emodin has been shown to be effective against MRSA by destroying the bacteria’s cell wall and cell membrane in vitro.

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 does this by addressing the infectious aspects of Lyme disease with its antibacterial and antispirochetal properties, but also addresses the symptoms through immunomodulatory and anti-inflammatory properties.

Resveratrol has been shown to cross the blood-brain barrier and can act therapeutically on the central nervous system (CNS) for those cases of Lyme’s that have also crossed. It also inhibits the cytokine cascade, which is one of the more disastrous effects of Lyme’s in the CNS.

It  contains anti-inflammatory properties that make it effective against rheumatic pain.

In addition to it’s potent anti-inflammatory and antioxidant properties, Japanese knotweed has a number of other mechanisms that may help protect against cancer – by normalizing cell differentiation, inhibiting metastasis, and inducing apopotosis. It can also restrict the formation of blood vessels in the case of tumors and malignancy.

In Traditional Chinese Medicine, hu zhang is used to invigorate the chi and clear heat, to remove toxins and ease pain.

Traditionally, it was used to help balance hormones in women going through menopause. Modern research now backs this up with evidence that it is a mild phytoestrogen which make make it effective in treating hot flashes.

Controlling the Spread

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.

Recipes Using Japanese Knotweed

Japanese Knotweed Purée

1. Gather stalks, choosing those with thick stems.
2. Wash well and remove all leaves and tips.
3. 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.
4. Add only enough water to keep from scorching, about half a cup.
5. Cook until pieces are soft, adding more water if necessary. They will cook quickly.
6. When done, the Japanese Knotweed needs only to be mixed with a spoon. Add lemon juice to taste and more sugar if desired.
7. 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.   http://www.eattheweeds.com/japanese-knotweed-dreadable-edible/

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.
2. 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  

1. Put the knotweed juice, lemon juice, and pectin into a large pot. Bring it up to a rolling boil.
2. Add all the sugar at once. Bring it back up to a rolling boil, and boil 1 minute while stirring constantly.
3. Remove from the heat and ladle it into hot, sterilized jars, cover.
4. Process in a water bath for 10 minutes   http://the3foragers.blogspot.com/2011/05/japanese-knotweed-recipe-knotweed-jelly.html

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°
2. place baking papers in a muffin pan.
3. In a saucepot, combine 1/2 c. sugar, the chopped knotweed stalks, 1/4 c. water and 1 Tbsp lemon juice.
4. Cook over medium heat for 10 minutes, stirring often.
5. Allow the stewed knotweed to cool. There should be about 1 c. stewed knotweed.
6. In a large bowl, whisk the egg with the oil, and stir in the stewed knotweed.
7. 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.
8. Fill the muffin papers about 3/4 full.
9. Bake for 24-28 minutes, until the top is set and springs back when touched.
10. Cool and serve with butter, or toasted.   http://the3foragers.blogspot.com/2012/04/japanese-knotweed-recipe-knotweed_02.html

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.   http://the3foragers.blogspot.com/2012/04/japanese-knotweed-recipe-knotweed.html