Weed Eater

Knot Weed Fool

Written By

Jen Rose Smith

Written on

June 01 , 2012

‘What is a weed? A plant whose virtues have never been discovered.” —Ralph Waldo Emerson

I planned the dinner with Emerson’s optimism and an eye on my backyard. Through spring’s soaking rains I watched Japanese knotweed swell beside the garden shed and was cheered by the sight of garlic mustard peeping up between the raspberry canes. When slender stalks rose amidst the mustard’s heart-shaped leaves and a few early flowers appeared, it was time to send out the invitations. “Dinner will be served at 7:30,” I wrote, then headed to the basement for the work gloves that had gathered dust since last October.

Since moving to the Northeast I’ve learned to love wild foods, and fiddlehead-ricotta tarts are hot sellers at my farmers’ market. But I like the idea of eating weeds even better. When the snow melted away this year, I saw tenacious invasive plants outgrow our casually tended perennials. Weary of a dark-months diet of beets and squash, I thought surely there was something good to eat among the spiny, bitter volunteers that were cropping up in the yard.

Transforming unwanted plants into dinner seemed like classic kitchen alchemy. I wanted to fill my belly and tend my ragged backyard at the same time, so I decided to dedicate a day to weeding and then cooking what I pulled from the ground. Although the species of noxious weeds that were crowding out the raspberries pose a serious threat to Vermont’s ecosystems, I was eager for ingredients; quietly, I began to urge on the much-reviled invasives.


Garlic mustard, Alliaria petiolata, is native to Eurasia and was introduced to North America in the 19th century as a culinary herb. Since that time it has made itself at home thanks to some clever adaptations, such as the production of allelochemicals that suppress mycorrhizal fungi in the soil, inhibiting the growth of other plants. The leaves contain natural anti-freezing agents, which allow the plants to overwinter unharmed, even in chilly northern Vermont.

Recipes abound for Alliaria petiolata, and I’d tried a few in the past. Last summer, I ground the rounded basal leaves into an inedibly bitter pesto. Still, someone liked the plant enough to bring it across the Atlantic and plant it in their garden as a reminder of home. Garlic mustard, I thought, deserved another try.

Japanese knotweed, Fallopia Japonica, came to the United States from Japan, where it is known as itadori, and is wild-harvested for food and as a medicinal plant. Like garlic mustard, it has a few culinary obstacles to overcome. Fallopia Japonica must be harvested when it’s very young and tender, and foragers describe the flavor as similar to rhubarb, but more astringent. Unsurprisingly, many recipes for using Japanese knotweed suggest cutting the taste with large quantities of sugar.

By yanking the knotweed and garlic mustard from my backyard, I’d be doing more than improving my raspberry crop. The state of Vermont considers both of those plants to be Class B noxious weeds, which means they’re non-native and “pose a serious threat to the State,” although they’re not so widespread as to be insurmountable. I figured that by knocking down a few weeds in my patch of the Green Mountain State, I was doing my patriotic duty, holding a front line against some very pushy flatland fauna.

If I was doing all that weeding I wanted to make it count. Both knotweed and garlic mustard can be pretty tricky to eradicate. Knotweed has an extensive underground rhizome network-horizontal plant stems that can extend up to 60 feet. When disturbed they send up new shoots, so digging it up doesn’t work. If knotweed isn’t too established, you can cut it just above the ground every year for several years, in hopes of weakening the organism. Little bits of the stem can germinate into entirely new plants, so it’s important to discard them carefully (and not throw them onto the compost heap).

By contrast, garlic mustard reproduces only by seed, but the seeds are viable for up to seven years and can mature even after the plant has been pulled from the ground. Because of the existing seed bank in the soil, getting the garlic mustard out of my backyard will be a multi-year project; it looks like I’ll be planning another weed-eating dinner party this time next year, and probably for the following six. Like Japanese knotweed, garlic mustard should never be thrown onto the compost heap. Any part of either plant that doesn’t get eaten should be taken to a commercial compost facility, or bagged and taken to a landfill.


The morning of the dinner party, I donned some gloves and headed for the garden. The situation was worse than I had thought. Garlic mustard was everywhere, entwined with raspberry canes, nestled up against the fence, and extending down the steep hill behind the house. I set to work, first filling a basket, then making several large heaps of the weeds. The ground was damp from a light rain and the plants loosened easily, roots intact. Somehow, much of the Japanese knotweed was already huge, with stems as high as my waist and fat as a roll of quarters. I chopped it down, bagging the big stems and saving the smaller stems for the kitchen.

When I’d cleared the yard of weeds, I had a giant pile of garlic mustard that I began to nibble from, sampling little bits of the various plants. I’d heard that some individuals are more bitter than others, and while a few leaves were too powerful for my taste, others had a strong but pleasant mustard flavor. To my surprise, I found that I preferred eating from plants that had already flowered. With so many to choose from, I harvested leaves selectively, taking small, triangular leaves from the top third of the stem.

I went inside and gently cooked these in butter, melting them into a dark green heap. The bitterness was still pronounced, so I balanced it by incorporating it into a rich quiche along with sweet, caramelized onions. To emphasize the mustard flavors in the dish, I added a thin layer of whole-grain mustard and finished off the slim tart with a dusting of sharp Vermont cheddar.

Moving onto the knotweed, I chopped the stubby stalks into chunks and simmered them with a bit of brown sugar. Once they were sweetened the flavor was pleasant, with a lemony taste that I liked. Since I’d waited until most of the knotweed grew tall and woody, though, I didn’t have enough of the smaller growth for the Knotweed Fools that I wanted to make, so I added a chopped pear to the simmering pot to make up the difference.

That evening, as my husband and I and some friends passed around plates heaped with Garlic Mustard Quiche, I looked with satisfaction at the garden, finally cleared of all those weeds. While I nibbled at my Knotweed and Pear Fool, however, I had to wonder if Emerson was right about weeds’ hidden virtues. Sure, I’d managed to turn a couple of Vermont’s invasive species into a meal, but only by combining them with enough butter and sugar to make cardboard appetizing. I wouldn’t love either plant in a salad.

By suggesting that weeds have qualities that are yet to be discovered, Emerson was challenging the way we classify plants but with a human-centric perspective that now seems naïve. The more I’ve learned about garlic mustard and Japanese knotweed, the more impressed I am by their highly adapted dispersal methods, their resilience, and their range. From their own perspective, Vermont’s noxious weeds are as virtuous as can be. So, I have to disagree with Emerson. Weeds have all kinds of virtues, from rhizome nets to allelochemicals, but it doesn’t mean that we, or Vermont’s native flora, are going to like them very much.

As far as eating the weeds, well, as long as I’m pulling them, I like the idea of turning them into dinner, and that quiche was pretty darn tasty. While garlic mustard and Japanese knotweed might bring an impressive array of adaptations to the table, humans have developed some effective tools to eat them. Until they stop cropping up, I’ll keep eating away at the weeds in my garden armed with butter, sugar, and a good pair of work gloves.

About the Author

Jennifer Rose Smith

Jen Rose Smith

Jen Rose Smith writes about food, drink, and travel, and is the author of the upcoming Moon Handbook to Vermont. She is a frequent contributor to Localvore Today and Best of Burlington, and likes her ice cider with a hunk of Shelburne Farms’ cloth-bound cheddar.

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