My friend Leda and I are partners in crime. We conspire to pick noxious weeds in a public park, which, technically, is against the law. I checked. The fine in New York City is $1,000 for removing plants from a park, although writing a ticket for picking an invasive plant like Japanese knotweed should make any self-respecting park ranger blush. When I weigh the tart, zesty taste of knotweed shoots against the threat of a hefty citation, the scales tip heavily in favor of the knotweed.
In the spring, Japanese knotweed sends up thick green spears mottled with red, like asparagus on steroids with a sunburn. Exactly when it muscles its way up through the earth depends on where you live. In New York City, the knotweed picking is best in April, so harvest earlier if you live farther south, later if farther north.
Before it starts to branch, knotweed is very tender; after branching, the stems are so tough that you have to peel them to eat them. That’s too much work for me, so I harvest early. Knotweed grows fast; within a few days, it’s gone from tender to tough, so when I see the first spears poke up, I don’t dawdle.
Some people think knotweed is bamboo, because of its tall, woody, jointed stems. It’s not closely related, but it’s just as invasive; by the end of summer, knotweed can be six to eight feet tall. The tall, dead stalks from the previous year’s growth make excellent markers for new growth in the spring, with the young shoots poking up around the old stalks.
On a fine April day, Leda and I saunter into the wilds of Manhattan’s Central Park. Our innocent-looking tote bags conceal not-so-innocent-looking bypass pruners. We know where the knotweed grows. Actually, knotweed grows almost everywhere, but in Central Park it’s most abundant in the Ramble, near the lake. And since the terrain is less inviting there (unless you’re cruising for a special kind of companionship), there are fewer meddlesome tourists and birdwatchers with binoculars.
Harvesting with Leda is great for many reasons. First, there’s the traditional camaraderie that comes from foraging; the quiet walking, the easy chitchat. Second, two pairs of eyes are better than one; one person can look out for park rangers with quotas to fill while the other harvests. And third, casual conversation is a surprisingly effective camouflage. There is no furtiveness here, no stealing under cover of silence. We are just two harmless women doing something confusing but clearly entirely legal. In the wild, conversation offers the additional protection of letting the wildlife know you’re coming, allowing it to make an unpanicked retreat. In Central Park, it takes a little more to drive off the wild beasts.
Japanese knotweed (aka Polygonatum cuspidatum aka Fallopia japonica) grows in sun or shade, in roadside ditches, on steep embankments, on boggy islands, and in Central Park. It was touted in the 1970s and 1980s as a quick-growing plant, useful for stabilizing eroding roadsides and creating windbreaks and living fences. Too late, environmentalists realized someone had made a big mistake. In the U.K. it’s now illegal to plant knotweed anywhere, and parts of the U.S. are following suit. Knotweed produces thousands of seeds per plant, and it also spreads by underground stolons. In Darwinian terms, it’s a very fit plant.
So in an effort to save the world, or at least a little piece of it, let’s all do our part and pull up as much Japanese knotweed as possible. Choose unbranched spears, between eight and 16 inches tall. They may be as thick as your thumb or as slim as a pencil. Sometimes you can snap them off at ground level, but a pair of pruners speeds the harvest. In less than half an hour you can easily pick five or six pounds of knotweed, enough for a batch of wine, some soup, and a couple of stir-fries.
Since there are so many things you can make with knotweed, you’ll have no trouble using as much as you harvest. And if you clean and freeze the stems when you get home, you can cook with it at your leisure; it keeps for months in the freezer. Knotweed wine is one of my favorite home brews; it takes less time to finish fermenting than many other wines and tastes like a good sauterne with a tawny gold color. Knotweed can be substituted for rhubarb in pies, jams, and jellies; it combines well with strawberries, blueberries, and apples. And, yes, you can use knotweed as a vegetable; it’s tart and crunchy in stir-fries and lemony delicious under hollandaise. My favorite way to eat knotweed is in a creamy soup. Nothing like turning environmental activism into lunch.
The park rangers haven’t caught us yet, nor has the local wildlife, human or otherwise. And the occasional birdwatching tourist usually moves along if Leda and I babble to each other in Greek. As for the average New Yorker, it takes a lot more than two women with bags full of knotweed to make one stop and stare. Unless it’s another enlightened forager; then we nod, smile, and continue with our rite of spring.
The author of Down and Dirty: 43 Fun & Funky First-Time Projects & Activities to Get You Gardening, Ellen Zachos is a former Broadway performer who recently recorded Green Up Time: A Botanical Look at Broadway, a CD that combines her two passions: music and plants.
Correction: As noted in the comments below, the scientific name of knotweed is actually Polygonum cuspidatum.
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