Smartweed: Nature’s Pepper and Pharmacy


Look for Smartweed in low, damp areas such as clean ditches. Photo by Green Deane

Polygonum punctatum: Smartweed

The blossoms are hot and bitter. Photo by Green Deane

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 very 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’s 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.

Blossoms can be be pink or white depending on the species. Photo by Green Deane

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 originally wrote this article. 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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{ 23 comments… add one }
  • Mary Meyer April 29, 2012, 8:42 pm

    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, 5:53 am

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

  • Jenny August 27, 2012, 3:53 pm

    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, 7:19 pm

      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.”

  • Martha June 5, 2013, 1:50 am

    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

  • mike August 12, 2013, 10:19 am

    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, 12:59 pm

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

  • Laurie December 19, 2013, 10:34 pm

    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.

  • Denise June 15, 2014, 11:10 pm

    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, 7:25 am

      Thanks for writing. I remember your ordeal.

    • margee September 19, 2015, 10:28 am

      I wonder who you are, Denise… I am also in Tulsa and am leading a foraging walk over at the botanical garden this morning and ran across this site. I too am trying to get people to see their yards in a different way. no need to destroy everything that doesn’t look like a blade of grass. I have smartweed, purslane, poke, dandelion, lambsquarters, wood sorrel and more that I allow to grow in my garden as it planted itself there and since it grows naturally and is highly nutritious, why no? isn’t that what you grow a veggie garden for anyways? my garden might not be as tidy as some but it works for me 🙂 I wrote a little children’s book about foraging last year. It sells in several great bookstores in Tulsa… Claire Goes Foraging.

  • Rebecca Wallace October 7, 2014, 2:33 pm

    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?

  • Cassandra Mottori October 6, 2015, 1:47 pm

    I am originally from Philadelphia, PA and smartweed grew along the drainage area along the fence of my property at the bottom of a hill, the soil stayed wet for a couple weeks after a rain and it was semi shaded from a maple that blocked the noon sun. At the time I didn’t know what it was, but I never mowers it down because it grew densely and was the only pink wildflower that grew without us planting it. As a kid I’d carefully taste all manner of plants, out of curiosity and because I always thought someday I could just collect weeds nobody waters and eat like a king. I can’t verify if it was specifically pennsylvania smartweed, but the pink buds have a distinct taste, kind of aweful photochemical and the leaves indeed taste like paper.
    But it’s not spicy at all!
    No smart weed I ever tasted in my life was hot(cause yeah, the Icky taste is oddly calming to chew)
    Incidentally I lived in Fern Park, FL for a year and a half a few miles from you Green Deane and loved to seek out nature trails, and oddly not once had I ever seen a single smart weed, and since it reminds me of my child home home in PA, I’d take notice.
    I now live in Alabama, just a mile across Perdido bay from Pensacola, FL never seeing smartweed the last 6 years I’ve lived here, neither in Alabama or Florida, when I found a shallow creek (more like a ditch) on church property going over a very large open grassy field, and lo and behold there was WHITE headed smartweed! Wondering if I’d been confused the last time I had read this article, I CAREFULLY chewed a leaf, it tasted more like an edible weed than the Pennsylvania variety, and THEN came the heat! Wow that smarts! JUST like capsaicin!

    I hadn’t noticed in your photo that the flowering head was white in the hot variety.

    • Green Deane October 6, 2015, 2:59 pm

      Thanks for sharing your history…. several Polygonums are edible but the quality varies greatly.

  • Kevin November 23, 2015, 12:27 am

    My great-grandmother, Lula Curry (1890-1977), said when she was a little girl, her family used Smartweed to catch fish.

    I don’t know if it is the same plant your article is about but she said they’d dam a section of the creek and take Smartweed and bruise it by pounding it on a rock and then spread it on the water above the dam. The fish would become paralyzed and they’d walk around picking them up and putting them in buckets and then have a big fish diner. I believe she said her parents learned it from the Native Americans in the Mingo County, WV area.

    Have you ever heard of that use for Smartweed, or do you know of another plant which has that property or use?

  • Jeffrey R. Aldrich February 9, 2016, 3:13 pm

    The chemistry of water pepper smartweed and related species (new genus name is Persicaria = Polygonum) has been described in the following publication:
    Prota N, Mumm R, Bouwmeester HJ, Jongsma MA. 2014. Comparison of the chemical composition of three species of smartweed (genus Persicaria) with a focus on drimane sesquiterpenoids. Phytochemistry
    Abstract-The genus Persicaria is known to include species accumulating drimane sesquiterpenoids, but a comparative analysis highlighting the compositional differences has not been done. In this study, the secondary
    metabolites of both flowers and leaves of Persicaria hydropiper, Persicaria maculosa and Persicaria minor, three species which occur in the same habitat, were compared. Using gas chromatography–mass spectrometry (GC–MS) analysis of extracts, overall 21/29 identified compounds in extracts were sesquiterpenoids and 5/29 were drimanes. Polygodial was detected in all species, though not in every sample of P. maculosa. On average, P. hydropiper flowers contained about 6.2 mg g FW1 of polygodial, but P. minor flowers had 200-fold, and P. maculosa 100,000 fold lower concentrations. Comparatively, also other sesquiterpenes
    were much lower in those species, suggesting the fitness benefit to depend on either investing a lot or not at all in terpenoid-based secondary defences. For P. hydropiper, effects of flower and leaf development and headspace volatiles were analysed as well. The flower stage immediately after fertilization was the one with the highest content of drimane sesquiterpenoids and leaves contained about 10-fold less of these compounds compared to flowers. The headspace of P. hydropiper contained 8 compounds: one monoterpene, one alkyl aldehyde and six sesquiterpenes, but none were drimanes. The potential ecological significance of the presence or absence of drimane sesquiterpenoids and other metabolites for these plant species are discussed.

  • Keith June 30, 2016, 11:10 pm

    Great work Green Deane,kept it going…

  • TrisTara October 7, 2016, 8:13 am

    I was wondering about processing it for medicinal purposes. Do you know where to get more information about how to do that?

  • jennifer October 25, 2016, 6:32 pm

    i am trying to identify a very similar plant. in fact the two are often found together around my ponds. BUT – the other plants has very pricky spikes all up and down its stem and they HURT like crazy when you touch them – you cant see them very well as they are so small, and they do not leave a persistent sting like a nettle, but while youve got it in your hand the sensation is like a nettle.
    anyway – does anyone know what this other nasty thing might be? looks a lot like the smartweed, but its not.

  • kate February 7, 2017, 1:44 pm

    I live in Pa. and attempting to create a meadow. Last summer, found jimsonweed datura stramonium. Collected seed heads and have tons of seeds but really collected for decorative use of seed heads. I read that this is in nightshade family. Should I get rid of seeds or plant them in “safe” area, again, just for seed heads. I did see bees enjoying flowers, however!
    Appreciate your suggestions

    • Green Deane February 7, 2017, 5:32 pm

      It’s a toxic plant, or at best a medicinal plants.

    • Ronald Maxwell April 14, 2017, 9:31 pm

      A lot of the new trumpet flowers that they have now are of the family of jispenweed. I heard kids would suck on the seeds to get a messed up head. But they have killed people. So whatever you do with them be very careful. Some are actually against the law to possess them because of them being used as a drug!

  • Tina October 11, 2017, 8:02 pm

    Nice info! Most if not all the “polygonums” are now in the Persicaria genus:
    If you do a general search for persicaria on the USF atlas you will see they have been moved. Jenny sure called the similarities!
    Thank the taxonomists!
    Cheers 🙂


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