"If you can't beat them, eat them."
Why foraging for invasive plants is good for you — and the planet.
On any spring day, donning gardening gloves and armed with shears, Amy Johnson scans her bed in the Fenway Victory Gardens. She’s looking for specks of green between her plants. Some call them weeds. To her, it’s lunch.
“You don’t have to live in rural areas or in the suburbs in order to forage. It’s definitely doable, even in an urban place like Boston,” said Johnson, who is working toward her master’s in gastronomy at Boston University.
Johnson, 31, is specifically looking for invasive plants — plants that the USDA says compete with native species for moisture, sunlight, nutrients, and space. They’re vigorous, hearty, and aggressive, lacking natural predators and free to expand, unhindered. The Massachusetts Invasive Plants Advisory Group has identified 72 such plants in the state.
This problem, says conservation biologist Joe Roman, is completely human-made. “They were brought over often on purpose.” Roman is the editor-in-chief of Eat the Invaders, a website dedicated to explaining the foraging and consumption of invasive species. Many were introduced as landscape ornamentals or garden plants. But quickly, they took over.
So what can be done? The Native Plant Trust recommends, first and foremost, preventing the plants from entering the state. But for many invasive plants, that ship has sailed.
It’s possible to destroy these plants through traditional methods, including herbicides, but studies have shown the chemicals aren’t great for humans. So Roman and many others prefer a different approach: eating them.
“We’re not trying to make it sustainable,” said Roman. “The goal is eradication.”
The Globe asked local foragers for recipes incorporating two edible (and quite tasty) invasives: garlic mustard and Japa
nese knotweed. Below is a detailed identification guide and some of the best recipes, with help from certified educator Rachel Goclawski, who runs the “Cooking with Mrs. G” YouTube channel.
But before we start, some important foraging rules.
R Do your research. Phone identification apps like iNaturalist are great but not perfect, and the consequences of choosing the wrong plant can be fatal. “You really need to do that extra little few minutes of work and check for key identifiers,” said Goclawski.
R Know your sources. Roman wants to emphasize that you need to know how the area is treated. “You don’t want to go where people are using a lot of herbicides or pesticides.”
R Know how to dispose. Goclawski preaches to her students that when you’re collecting invasive plants, be careful not to spread the plant around. Carry your foraged goods in a bag, be careful not to drop anything on your home, and, “don’t just throw it on your compost, let it die in a plastic trash bag for a while.”
GARLIC MUSTARD Tastes like:
A cross between fresh garlic and green onion. The leaves, slightly sharp and bitter, with a garlic-y twist. The flowers, spicy — like horseradish.
How did it get here? It was likely introduced in the state for its use in cooking, according to Mass Audubon. It’s a biennial plant, meaning it lives for two years, blooming in the second year with small, white flowers.
“Incredibly prolific, it’s everywhere,” says Goclawski. It invades fields and woodlands, releasing a toxin that limits the growth of other plants nearby.
How to identify: Heart-shaped leaves with lots of veins. The first year is rosette-shaped, with scalloped edges. Nearby, you’ll find the second-year plant, with a tall flower stalk.
Goclawski recommends using all five senses when identifying any plant, especially garlic mustard. “If you’re in doubt, just rip a leaf. It should smell really strongly of garlic and mustard,” she said.
How to harvest: Pull the whole thing up, root and all.
How to eat it: In pestos, pies, or any way you would use a green, leafy veggie, but be sure to boil it. Garlic mustard, like all mustard greens, contains a small amount of cyanide, but it is water-soluble, meaning water dissolves it.
Pesto recipe
From Ryan Ralston, chef and general manager at Bread & Roses in Hyannis
2 cups fresh, and boiled garlic mustard leaves, or 1 cup frozen garlic mustard puree, thawed
2 cups fresh basil
1 cup sunflower seeds
2 to 3 cloves garlic
1 cup olive oil
2 teaspoon kosher salt
1 teaspoon black pepper, freshly ground
Pour 2 cups of boiling water over 1 cup sunflower seeds. Let soak for 30 minutes, and drain well. Combine all ingredients except olive oil in a food processor and blend on high for 60 seconds. While the food processor is running, slowly drizzle the olive oil until fully combined. Season to taste.
JAPANESE KNOTWEED
Tastes like: A lemony rhubarb. Tart, crunchy, and sweet.
How did it get here? It was brought over from eastern Asia in the late 19th century and used as an ornamental privacy barrier. It’s fast-growing, up to 8 inches per day, and strong enough to break through concrete.
How to identify: Look for heartshaped leaves. The stems are a distinctive green with red stripes. There may also be signs of last year’s plant, which looks like wooden bamboo.
When to harvest: As early as possible, preferably from late March to early May.
How to harvest: Cut the small shoots from the base. Goclawski says they’re the most delicious. If you want to dig deep, there’s gold. Japanese knotweed is packed with resveratrol, the same compound in red wine that has been linked to a lower risk of inflammation and blood clotting.
How to eat it: Raw, substituted for celery as a dipping vessel. Sauté with butter and salt. Chop it up and pickle it. Treat it like asparagus and roast it or pan-fry it.
Japanese knotweed crumble
Andrew Devine of New Hampshire says he follows “a strawberry rhubarb crumble recipe and [substitutes] knotweed for the rhubarb.”
Japanese knotweed Gin recipe From Scott Place, Rockport 750ml bottle of vodka (preferably 50 percent ABV, but 40 percent is fine). Retain the bottle. 2 cups of Japanese knotweed shoots, chopped into ½ inch pieces
Seasonings: Juniper berries, crushed (or more to taste); ½ cup coriander seeds; ½ teaspoon cardamom seeds, crushed; 2 bay leaves; 1 teaspoon black peppercorns; 1 teaspoon pink peppercorns; 1 cinnamon stick; peel of two lemons.
Add all ingredients to a glass jar and leave for a week, stirring occasionally. Taste and add extra crushed juniper berries if desired. Allow to macerate for two more days. Strain through a colander lined with cheesecloth. Pour into the original vodka bottle. Gin can be enjoyed immediately but gets better after about a month.