Water Pepper – A Foraging Guide to Its Food, Medicine and Other Uses

As I write this I am sitting on a bench. Opposite me is a large patch of water pepper. I write with an ancient, primitive tool. A pencil that creates my scribblings on chequered paper in my journal.

This morning, water pepper rises up amongst the Himalayan balsam as I sit on a bench overlooking a virtual forest of this green friend.

There is a chill in the air, and the sun shines down on me, as it does for us all. Regardless of our status or temperament.

Simple pleasures. Sitting with green friends. No phone. No digital disconnection. Just here. Feeling, breathing and smelling my local ecosystem.

Most of the stands are knee-high, and water pepper can also reach waist height.


Marshpepper, annual smartweed, smartweed, arse-smart.

Scientific Name

Persicaria hydropiper



Botanical Description

Stems 1-2 feet high, often decumbent at the base. Stipules fringed. Leaves lanceolate, wavy. Flowers in slender drooping spikes, the clusters of flowers almost all distinct. The perianths dotted with small glands.




Cultivated land, marsh, meadow, ponds, riverbanks, wasteland.

Harvest Time


Parts Used

Shoots, leaves and tips.

Nutritional Profile

Protein 7.54%. Fat 1.86. Carbohydrate 7.99%. Ash 1.99%. 1 The leaf contains essential oils. 2

Use of Water Pepper As Food

Not much is mentioned in the wild food cookbooks about water pepper.

With its willow-like leaves, the older ones are dark green similar to how an old lime might look in colour. The young tips and flower buds are what wild epicureans seek.

Pick a small leaf from the top, and in a short moment, this humble looking plant kicks serious ass as heat tears through your palate. Chillies eat your heart out! It is similar in heat to Tasmanian pepper.

This is wild, feral, pungent heat, yet once it subsides it leaves a pleasant taste.

It is the bicyclic sesquiterpenoid, polygodial that is responsible for the pungent taste, and it is almost impossible to substitute it with any other spice.

Rummaging around the food record I find barely any reference to water pepper being used in Europe. So I keep looking. I鈥檓 interested in any possible historical use for it.

My journey takes me east to Japan and South East Asia, where I discover the leaf is traditionally used to garnish sushi. Move over wasabi.

The leaves are also mixed with vinegar (the record doesn鈥檛 say what type), and soy sauce.

This dipping sauce is called tade su and is served with ayu (sweetfish).
This makes me curious, maybe it would go with small sardines or fresh Cornish pilchards would work.

My water pepper recipe is a variation on the Japanese one. As no quantities where listed in the original version, I had to make them up. A dash of this, a dash of that.

I served it drizzled over prawn cocktail on avocado (I know, how very 1970s.), shared with a dear friend. We both agree. This is something very special.

Water Pepper Recipes

Wild Tade Su

Other Uses

The stalks produce a yellow dye. 3

Safety Note

Rare reports of some people experiencing blistering after handling the aerial parts. 4


  1. Read, B. (1982). Famine foods list in the Chiu Huang Pen Ts’ao. The Botany of mahuang. Common food dishes of Shangai. Taipei: Southern Materials Center.
  2. Peter, K. (2012). Handbook of Herbs and Spices. Cambridge: Elsevier Science.
  3. Coon, N. (1975). The dictionary of useful plants. Emmans, Pa: Rodale Press.
  4. Clapham, A., Tutin, T., Warburg, E., & Roles, S. (1952). Excursion flora of the British Isles. Cambridge University Press.

Share Your Experience. Leave A Note For Others

  1. Sure have something that LOOKS LIKE the water pepper. Are the tiny flowers white when open inside pink sleeve? I could send a photo. BUT, no hotness in even the youngest leaf. Incidentally, the leaves on this are covered in short hairs that point to tip, top and bottom.
    Writing from Grafton, NH, US

    • John – I don’t know, best to grab a wild flower book and key it out. To be honest, as much as I would love to ID plants for people I have over 20,000 people on my mailing list, and it’s just not feasible.

  2. Thanks for a very interesting, enjoyable and extremely well-written article! I identify with your comments on time spent in silent contemplation. Our ecosystem is so utterly amazing that words cannot adequately describe how wonderful it all is.
    I believe we can all benefit from spending time in silent contemplation of nature, and that if everyone would so spend, on most days, even a little time, we would benefit as a society and as a species. Our world be a better place.
    May all positive energy be with you.
    Keep up the good work!
    Rolande / Rolo (P.S. Initially I accidentally posted this as a comment on the recipe; please remove it if you can – I can鈥檛!).

  3. Loads of it here on the east coast of the United States.
    I’ll taste it the next time I see some!
    As always, thanks for the great info!

  4. I was told that the reason The plant is called smart-ass is that it was used in stuffing for the bedding, to keep the bugs away. Also, the plant looses its peppery properties if heated. So, having it in vinegar makes sense. I鈥檇 also like to try drying the seeds to see if they keep the kick.

  5. Wicked, will give me something to look out for while canoeing this weekend 馃槈

    Thanks Robin, this is a new one for me. Awesome work

  6. It’s funny reading your article as it reminds me that just a few weeks ago I met you at the Wild Herb Week-end, NC Herbal Conference, and a friend and I stopped you as you were walking by, and we asked you what this plant was, and you said it was a smart ass, and I thought for a moment that you were the one being the smart-ass. Oh my goodness, funny times.

  7. Have it growing here in Dorset omg it’s hot one bite lulls you in its nice not much to it then it hits you most definitely would make your arse smart lol ? good article as always Robin

  8. Great article. Just found this plant myself while trying to key out Persicaria odorata. Thanks, definitely going to try mixing some with vinegar as a condiment.

  9. Polygodial is responsible for the pungent test of Persicari leaf, it binds to the same receptor as peeprin, an active component of black pepper. And tesat is similar. but Eurpoenas spend enormous resources and wasted lives of thousands of sailor and killed millions of natives in their quest for black paper, while herb with similar test was weed readily available in the countryside


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