Wild Edibles: How to Eat Japanese Knotweed

Disclaimer: Eating certain wild plants can be deadly!!

Be certain to consult a professional (or a really good field guide) in order to positively identify this plant before trying this for yourself. The owners of this site will not be held responsible for any lapses in judgment or stupidity when handling or consuming wild plants.

Japanese Knotweed (Fallopia japonica) is one of those plants you’ve probably seen a hundred times but haven’t realized it.

A native to southeast Asia, it was introduced to the United States in the late 1800s as an ornamental and has since become one of the most invasive plants in the United States, quickly spreading across to more than 40 of the 50 states. It’s root system is so invasive and strong that it can damage foundations, buildings, flood defenses, roads and so on.

Despite its bad rap, Japanese Knotweed is a great source of food and medicine and one of my favorite wild edibles in the early Spring. And since it is an invasive species, you don’t feel bad about over-harvesting it. In this post I’ll explain how to identify and harvest Japanese Knotweed and how to make a simple but delicious recipe from your foraging.

How to Identify Japanese Knotweed

The problem with Japanese Knotweed is that once you typically notice it, it is usually too late to harvest for food. In early spring, it starts out as a humble shoot that quickly grows (over an inch a day!) into a mature plant reaching upwards of 10 feet high.

Although the time to eat it is in the early spring before it begins to turn woody (under 12 inches), you’ll want to be able to identify it during its later stages of growth as well so that the next year you can return in the early spring and harvest it.

Spring Identification

Spring is the time you should be on the lookout for this plant. Here’s what to look for:

In the early spring red/purple mottled green shoots appear from the ground and grow rapidly forming canes. This is the ideal time to harvest the Japanese Knotweed shoots. You’re looking for 6 inches or less.
Late spring shoots with initial branching. You can still harvest the plant at this point as long as it is under a foot. At this stage you’ll need to peel them before consuming, since the outside has begun to get more fibrous.

Summer/Fall Identification

By summer this plant has grown to its full size. Since it typically grows from a networked root system, all of the individual mature plants form what appears to be a large shrub:

Here’s a good example of how the knotweed comes to form what looks like a large shrub.
Bamboo-like canes.
Shield shaped leaves that are aligned in an alternate pattern.
In the late summer you’ll also begin to see the flower growth.

Late Fall/Winter

During late fall and winter the knotweed’s energy will begin to travel back into the root system in preparation for the winter time. During this time the leaves fall and the stems die and turn brown. The stems (canes) typically stand during the winter which can serve as a good indication of next year’s growth.

Since it grows in colonies, the winter skeletons are easy to identify from afar.

How to Eat Japanese Knotweed

While you can eat Japanese Knotweed raw (it is tart and crispy and tastes very similar to rhubarb), ideally you’ll want to cook it. Since it tastes very similar to rhubarb, you can use Japanese Knotweed in any dish that calls for rhubarb – my favorite being strawberry knotweed pie…yumm.

Here’s a simple dish that I got from Steve Brill that I love:

Japanese Knotweed Surprise

Ingredients (for one serving)

  • 2 cups sliced apples
  • 1 cup sliced Japanese Knotweed shoots
  • 1/2 cup apple juice
  • sugar to taste (optional)
Step 1: Gather your harvested knotweed and remove any leaves and stems.
Step 2: Chop the knotweed into a small enough size to fit into your cooking pot and peel those shoots which have begun to form leaves (these will have already begun to turn stringy).
Step 3: Throw the knotweed and chopped apples into a pot and pour apple juice on top, bring to a boil and begin to simmer.
Step 4: Simmer for about 20 minutes or until soft. You will notice that the knotweed seems to melt into a thick, sauce-like consistency.
Step 5: Once the knotweed turns to a sauce-like consistency, serve and eat!

Japanese Knotweed Nutrition and Medicinal Information

Japanese Knotweed provides an excellent source of vitamin A and vitamin C. It also provides potassium, phosphorus, zinc, and manganese.

Japanese Knotweed is also an excellent source of resveratrol, the same substance in the skin of grapes and in red wine that reduces bad cholesterol and lowers the risk of heart attacks.

According to master herbalist, Stephen H. Buhner, Japanese Knotweed is very effective when it comes to treating and preventing Lyme’s disease. As an anti-inflammatory, it also helps the immune system to combat various infections, relieves symptoms of arthritis and can protect the body against neurotoxin damage.

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32 Comments»

Comment by Amy Hassenpflug
2011-06-03 10:25:39

I presume since it grows in 40 of the 50 states that it grows in Virginia. However, I cannot remember ever seeing it. Am I correct that it is available here in Virginia? Thanks for all your GREAT information!

2011-06-05 21:09:25

Amy,

Knotweed definitely grows in Virginia. It is more prevalent inland than near the coastal areas so keep you eyes out for it.

Thanks for visiting!

- Erich

 
 
Comment by Mike
2011-06-03 18:49:44

Great page I was looking for info like this. I post a video on Youtube asking for some help on the plant ID.
http://www.youtube.com/watch?v=_awweTg81ww

2011-06-05 21:11:36

Great video Mike. That’s definitely Japanese Knotweed. Be sure to try it out in the early Spring.

 
 
Comment by kialey
2011-06-27 14:21:34

this plant species has the ability to regenerate itself from any part (leaves/ stems). In picking this plant you could accidentally be spreading and invasive species and harming the natural environment. if any part of plant is lost b/t the field and eating it it could start a new population of Japanese knotweed.
i dont mean go all environmentalist on you, i just thought you might want to know.

Comment by Tactical Intelligence
2011-06-27 15:06:54

Kialey,

No, you’re absolutely correct. I’ll be sure to update the article to include a warning about that.

 
 
Comment by Sandy
2011-07-12 18:50:57

I’m if the leaves of the full-grown plant are edible in a salad? I can’t seem to find any information on them, all of the information I see online states using only the young shoots.

 
Comment by Sandy
2011-07-12 19:04:52

In reply to my own question, I found the following article stating that the “Leaves, Stems, Roots, and Seeds” of the Japanese Knotweed plant are all edible. http://scotspine.net/jap_knotweed.html

2011-07-12 20:10:03

Thanks for the great link Sandy. I’ve never tried the leaves personally (and didn’t even know they were edible to be honest) so I’ll need to try that out and let you guys know…

 
 
Comment by Robert MacElvain
2011-09-10 14:37:45

Where can I purchase a few Japanese knotweed rhizomes?

Robert MacElvain
macelvain@gmail.com

 
Comment by Linda Hinchey
2012-02-21 17:16:21

I love your blog. I’d like to note that Japanese Knotweed is not a wild native plant and is extremely invasive. Not only is it bad for the environment where it is planted and spreads but it will choke out anything else you try to plant in your yard and is nearly impossible to eradicate. Spreads fast underground by the tiniest of root hairs. You would be shocked at what some folks have tried to kill it. I have a patch that came in with a load of gravel and it’s been a nightmare ever since. Maybe I should start selling it. ;)

Comment by Tactical Intelligence
2012-02-22 23:33:01

You’re absolutely right. However since it is here and available we should definitely make use of it. Absolute care needs to be taken that what you gather you use or like you said you can further exacerbate the aggressive nature of this plant.

 
 
Comment by elsa isaac
2012-04-23 16:57:14

I have knotweed. Boys do I ever have knotweed! However I am of the sort if you can’t beat it..Eat it. Thanks for the info.
However, I have a question. I have some just as described here with the white flowers as well as another very same plant, but it gets red flowers in the fall. It is a different variety? Just curious if you or anyone knows info about this?

 
Comment by Pete Appleton
2012-04-27 18:30:00

Whilst I am a big fan of eating wild edibles, especially invasives – having worked in conservation and witnessed the battle against Japanese Knotweed, I see two issues:

1) This may be against the law in certain areas. In the UK, for example, you need a specific license to remove Japanese Knotweed from a site. This is for good reason – Japanese Knotweed is highly invasive and even just the tiniest bit on the tread of your boot can spread it to a new location.

2) I am concerned after seeing Knotweed treated with high levels of pesticide. You might, unwittingly, go and eat some that has just been blasted with the stuff a few days ago. This probably isn’t good. Then again, it could conceivably be a similar dose to the standard dose than your Roundup Ready “food” served up in the US.

Despite both of these, a friend once treated me to some Japanese Knotweed wine that he had brewed himself. It was fantastic, and washed down our wild mushroom omelette beautifully!

 
Comment by bry8iyze
2012-12-03 16:09:52

Herbicides (not pesticides!) are often sprayed on stands of this invasive weed so don’t collect from stands along roadside or utility right-of-ways, abundant as they may be. This weed often propagates along streams and rivers where herbicde use would not be allowed so that is a pretty safe place to collect. Just don’t add to the invasion by letting plant scraps fall!

Comment by Tactical Intelligence
2012-12-03 23:15:59

Thanks for the good info.

 
 
Comment by Mary
2013-04-13 01:30:35

you never give the techical (dont know the word i need) nane so i can check them out in Australia as same of your names are different to us over here. but thankyou for great site. know im going to find good info on it

 
2013-04-18 18:47:24

Hi Mary,

The word is in the first sentence, “Fallopia japonica”.

thanks for visiting!

- Erich

 
Comment by Elizabeth Mills
2013-05-10 14:15:07

I have this growing all over my hill side invading everything. How can I kill it out in some places, I would leave it over by the fence line but it is in my flower beds. Help.

 
Comment by john
2013-05-14 20:56:10

Have you eaten the seeds, what did they taste like.

 
Comment by Matt
2013-06-07 23:50:30

Thank you we have this growing in our garden and had no idea what it was, then magically found this and now I now. Glad to know that this is a healthy plant not just another weed like we had heard.

 
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2013-06-08 11:31:27

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Comment by Rosetta Ladesma
2013-06-24 20:19:56

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Comment by Gord
2013-07-09 15:05:58

Thanks for a great information source.
I’ve been wondering about harvesting during the summer. All of the sites I see suggest to only harvest in the spring, when the new shoots are 15-20 cm. I’m finding loads of new shoots midway through the summer (surrounding an existing stand, so I’m sure they are from the same root system)

Are new shoots still safe to eat later in summer? I’ve tried eating the entire thing (stem, shoot, and leaves) by steaming for a minute. They taste a bit bitter, then quite sour, but so far I haven’t died…

 
Comment by Juliana
2013-08-06 15:55:38

Admiring the hard work you put into your site and in depth information
you provide. It’s nice to come across a blog every once in a while that isn’t the same out of date rehashed information.
Fantastic read! I’ve saved your site and I’m including your RSS feeds to my Google account.

 
2013-08-08 11:49:41

Hi to every body, it’s my first pay a quick visit of this website; this website contains remarkable and truly fine material in favor of visitors.

 
Comment by Tom Seymour
2014-03-13 15:04:29

I’m not convinced that a Japanese Knotweed leaf dropped on the ground has the ability to regenerate. The same would hold true for the stem. The root system is a different thing. It does regenerate. But most knotweed patches extend their range with human help. The next time the road crew uses state or federal highway dollars to make another roadside ditch…”make work projects,” in other words, take note if they disturb a knotweed patch. If so, you’ll eventually see a long ditch filled with knotweed. But it’s not the plant’s fault.

I don’t mean to insult anyone by my skepticism. I do plan on trying to see if I can make my own knotweed patch spread by leaves or shoot cuttings. I have had difficulty in getting knotweed to grow in the gravelly, moist soil where I planted it. Groundnut vines, also growing on the same site, strangle the knotweed, killing many plants.

 
Comment by Jonah Gadoury
2014-04-24 15:36:11

So I had this brilliant idea to substitute rhubarb with knot-weed the other day for a strawberry – knot-weed spring desert…you got me!

 
Comment by Janet Pesaturo
2014-05-13 13:27:24

Hello, and thanks for the great article. I am wondering at what stage the stalks become inedible. Can you eat the stalks after they are 2 feet tall, of just when they are small shoots?

Comment by Tactical Intelligence
2014-05-15 10:24:14

Hey Janet,

Yeah, they start getting pretty woody after around a foot tall. At two feet they’re pretty much unusable.

 
 
Comment by Suzanna Love
2014-05-19 11:38:29

Thanks! I was wondering about that as I was tearing it out of the ground. I suspected as much and, luckily, have never put it in the compost heap. Now, my attack will be on two fronts- I shall,also, cook it and drink the tisane for my arthritis.

 
Comment by Suzanna Love
2014-05-19 11:48:13

Hello, Steve Brill, et al.,
If you boil it at any stage, will it yield a drinkable liquor? And will that liquor/tea/tisane/tincture have the same health benefits as using just sprouts?

 
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