Smartweed: Nature’s Pepper and Pharmacy

by Green Deane

in Flowers, Grain/Nuts/Seeds, Greens/Pot Herb, Medicinal, Miscellaneous, Plants, Roots/Tubers/Corms, Salad, Spice/Seasoning

Look for smartweed in damp places with full sun

Polygonum punctatum: Smartweed

Try only a very small amount at first

I can remember my first taste of a smartweed leaf… kind of like trying a piece of burning paper. Indeed, a lot of plants resemble smartweed but one quick taste and you’ll know if you’ve got the right plant: If it isn’t peppery, you picked wrong. Actually, the burn is not immediate. It takes a few seconds to kick in and then it intensifies. And about the time you wish it would stop intensifying it is just getting started. Word to the wise, use sparingly and try only a very small piece to start with chewing between teeth and tongue.

It’s a little hard to stuff inside the head, but the smartweed, Polygonum punctatum, (pol-IG-on-um punk-TAY-tum) is in the the buckwheat family, but you would never use it on morning pancakes.  It’s for seasoning, soups, and perhaps salads. Not only is it burning hot but some varieties, especially P.  hydropiperoides, (hye-dro-pie-per-OY-dees) are also vasoconstrictors. So if you have high blood pressure, go easy on those species. It’s all right as a spice, a bit much as a pot herb.

The Smartweed is common throughout North American and nearly year round in the southern range. Actually it is easy to identify even when brown dead and is still peppery. It has freely branching stems and a lot of joints which gives the plant its name. Polygonum is Greek for many knees. Punctatum means dotted, referring to dots on the tepals, and indeed it is also called Dotted Smartweed. It’s a fine plant for seasoning while camp cooking, but can overwhelm like cayenne pepper. Also be careful because some people can develop dermatitis from it.

Polygonum hydropiperoides

There are three species locally, all useable: The P. punctatum as well as P. densifolrum (compactly flowered) and the aforementioned P. hydropiperoides (water pepper.) P. hydropiperoides has tannins, rutin (3% in leaves) quercitin, kaempferol and some protein. It is considered a diuretic and has been used to stop intestinal and uterine bleeding, hasten menstruation and to treat hemorrhoids. It has many more applications as well. The Indians also cooked the leaves of the trio and ate of them sparingly. It’s also a common waterfowl food. If you crush a bunch and put it in a small body of water it will force the fish to float to the top by interrupting with their oxygen uptake (as does American Beautyberry.)

I saw some P. hydropiperoides in Mead Gardens, Winter Park, Fla., the day I wrote this essay. It was flowering and taking on a bit of fall red. It had been a while since I had seen the P. hydropiperoides, the P. punctatum being the one my path crosses most often. Soooo, I tried a good part of a leaf…. the hole in my tongue should heal in a few days. The blossoms are hot as well but are also bitter.

Some Polygonums have edible roots, perhaps the best know is P. bistorta, a Eurasian import. The roots are first soaked in water then cooked in embers. Or it can be chopped up, soaked in many changes of water, then passed through a mill to make a puree. The bulbs of the P. viviparum have been eaten raw but they are better roasted. The roots of the Polygonum multiflorum are also edible raw or cooked as are the roots of the Polygonum bistortoides  The seeds of the Polygonum douglassii, Polygonum aviculare and the European Polygonum convolvulus have been eaten since mesolithic times.

And while the Smartweed is called “many knees” at one time its name was arsesmart. I have never found any reference to what chemical(s) make the species peppery. Lastly, I have a video on the Smartweed on You Tube… made it in the rain… dedicated I am…

Green Deane’s “Itemized” Plant Profile

IDENTIFICATION: P. punctatum: Alternate leaves are smooth-edged, lance shaped, willow-like, one to six inches long, leaf base forms sheath around stem. Young leaves flat, older leave  can be wavy,  The stems are often reddish, flowers are small, pink or  white in dense clusters from the leaf joints or stem apices. It can grow to four feet or more but is usually smaller.

TIME OF YEAR: Year round in Florida, seasonal elsewhere, blooms July to first frost.

ENVIRONMENT:  It likes moist areas.  I often find it in the center part of old woods roads where they dip down and collect water or stay moist.

METHOD OF PREPARATION: In Asia the seedlings (sprouts) are collected and used like spicy radish sprouts for a hot flavor. Mature leaves and stems chopped up and used sparingly as pepper, leaves and stems boils in soups, again sparingly.  Numerous herbal applications.  The roots of some species are edible cooked, some require a little cooking, others require much cooking. The seeds of some are also edible. Check with a local expert about your local Polygonum.


A Mem-Inst-Oswaldo-Cruz. 2001 Aug; 96(6): 831-3. Abstract:Polygonum punctatum (Polygonaceae) is an herb known in some regions of Brazil as “erva-de-bicho” and is used to treat intestinal disorders. The dichloromethane extract of the aerial parts of this plant showed strong activity in a bioautographic assay with the fungus Cladosporium sphaerospermum. The bioassay-guided chemical fractionation of this extract afforded the sesquiterpene dialdehyde polygodial as the active constituent. The presence of this compound with antibiotic, anti-inflammatory and anti-hyperalgesic properties in “erva-de-bicho” may account for the effects attributed by folk medicine to this plant species.

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{ 11 comments… read them below or add one }

Rebecca Wallace October 7, 2014 at 14:33

We bought a plant once with a variety of smartweed growing in it. We have never seen such a giant version of this plant. Of course we didn’t think it would spread so quickly and allowed it to grow. A year later we find monster smartweed everywhere. The critters eat it …leaves and seeds. Do you know if this kind is edible for humans?


Denise June 15, 2014 at 23:10

Hi Deane:
Just happened across your site while looking for stories about smart-weed. Very interesting, if I didn’t know I might have thought you read my mind when you wrote this. I live in Tulsa OK. and made the news that went global in 2011 when I sued my city code enforcement for destroying my entire edible yard including my smart-weed. Lucky for me I had given several people some plants and was able to recover some of theirs. Love this plant and use it for sinus and arthritis . Just yesterday at a neighborhood block party I was able to introduce 2 elected officials and about 50 other people to this as well as many other wild edibles growing within 1 city block. One of the officials after tasting 1 leaf and still enjoying it on his tongue then took the plant I gave him to grow himself ate the whole thing in 1 bite. I am still wondering if his head popped off. Thanks for your site and the opportunity for everyone to share and enjoy all of the stories. Keep up the good work.


Green Deane June 16, 2014 at 07:25

Thanks for writing. I remember your ordeal.


Laurie December 19, 2013 at 22:34

A Native (Mohawk) friend of mine told me they use smartweed in their pickles. Traditionally, the only person allowed to handle the pickles is the person that made them or they will sour. I have no idea of the quantity of smartweed they use but it could be an interesting experiment next summer to try. Very grateful for the extensive knowledge that you share. There is so much incorrect info out there, it’s nice to have a trusted site to come to, to double check my findings. I am saving up to buy the video set. We don’t watch t.v. but I think I will be glued to my laptop for a few hours.
Thank you so much. Your work is greatly appreciated here in southern Ontario, Canada.


mike August 12, 2013 at 10:19

So, what do i eat on this plant? I have this growing in my garden, I thought it would produce a actual pepper. Thanks Mike


Green Deane August 12, 2013 at 12:59

Unless you have a wet garden it would be unusual for it to grow in a garden.


Martha June 5, 2013 at 01:50

We have a shallow area beyond our stock tank and it’s growing wild with smart weed. My husband LOVES spicy foods, and I’m wondering how to incorporate some of this plant into some of our meals. Any ideas about some culinary properties???

thanks! Martha


Jenny August 27, 2012 at 15:53

Hi Deane,

Can you offer any clarification regarding the (edible, though not very yummy) plant commonly known as Lady’s Thumb. I have seen the species names Persicaria vulgaris as well as Polygonum persicaria attached to this common name, and it does look quite similar to your Polygonum punctatum, above, though I have never noticed any spiciness to the “Lady’s Thumb” I have nibbled on in Chicago. As a spicy food aficionado, I would look forward to trying Smartweed, so I’ll keep my eyes out.

Thanks, and as a first time question-asker I’d also like to tell you how many delightful hours I have spent on your wonderful website. This is truly an invaluable resource…and a fun read, to boot!


Green Deane August 27, 2012 at 19:19

Thanks for writing. Cornucopia II says on page 185 of the Persicaria vulgaris that “young shoots and leaves are eaten in salads, stir-fried, or cookd briefly in boiling water and served with butter or vinegar.”


Mary Meyer April 29, 2012 at 20:42

I wonder if the arsesmart might be the effect it has on the hind end when one deficates after eating it. What do you think?


Green Deane April 30, 2012 at 05:53

Interesting idea… my thinking had not gone to that end…


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