Young Japanese knotweed.
By Linda Santucci Fondulas
As you ramble along in your car or bike on a winding second-class Vermont road in autumn, the spectacular brushstrokes of foliage before you captivate no less than the swaths of white blooms on tall bushy plants lining the rivers and brooks. This pleasing site would certainly not induce a knot in your stomach, yet that is precisely what it should do… in more ways than one.
If only we knew then about the common fleece flower, a.k.a. Mexican (or Japanese) bamboo or monkey weed. What we know now is that in the Victorian era science also reigned and flora and fauna traveled willy-nilly around the world. This one ornamental from East Asia traveled the globe west to Germany and then to the Royal Botanical Gardens, where it is known as Fallopia japonica.
Botanically known in North America as Polygonum cuspidatum, the U.S. Army Corps of Engineers eventually encouraged its planting along roadsides to help with erosion, and here and now we are on a mission to demolish what they have sown. Here and now we also know it by another moniker: Japanese knotweed, a knockout ornamental.
However good the intention of introducing this large herbaceous perennial plant, we are told it has become an invasive species—a monoculture dangerously dominating and disallowing competition.
Though it has slowly spread this past century to become a minor problem in Vermont it is now near crisis since 2011, when Hurricane/Tropical Storm Irene devastated Vermont rivers and streams at the end of summer. The multitudinous rhizomes in its root system broke apart with bits floating in high floodwaters all along flood plains. When the water subsided, these rootstalks quickly took hold wherever they happened to favorably land in the aftermath of disturbed soil.
Of the many solutions to prevent its further spread, the most often heard is, unfortunately, to repeatedly apply weed killer. I’ve also heard about smothering under plastic, vinegar solutions, excavation, burning, and a combination of all of these.
I heard Mike Bald of Choose Wisely VT give a presentation about Japanese knotweed. He is persistent in trying to convert chemical users to practice his method of photosynthesis starvation. He says, “The approach is to condense extensive infestations into hotspots. Set up weed-drying stations on pallets at the ends of each large patch and then flush-cut for three growing seasons. 10-9-8 seems to be pretty successful around here; 10 cuts the first year, nine the second, and eight the third. Depending, you may have to [use] Roundup.”
In China, knotweed, called Hu Zhang, has long been harvested for medicinal purposes. With its leaves high in oxalic acid it is used in association with Lyme disease, coughs, gum disease, hardening of the arteries, hot flashes, gout, and sore throats, to name just a few maladies. In the United States, for medicinal purposes, there is some suggestion that further study is needed, even stated so by Dr. Andrew Weil, a pioneer in integrative medicine.
A place on the menu
Knotweed is often a curious find on foraging excursions but as an edible perhaps we should embrace it. Green Deane in his blog Eat the Weeds calls it the dreadable edible. Eating knotweed is an approach we can all implement to keep this vegetal offender at bay, even if you are not a landowner.
For cooking or pickling, harvest young reddish shoots in early spring when they are 5 to 6 inches tall. They look like asparagus but with hollow stalks like bamboo. Recipes range from strawberry knotweed pie and knotweed sherbet to knotweed wine.
Most culinary uses of knotweed mimic those of rhubarb, so think compote, pies, jams, and crisps. Knotweed can be combined with rhubarb in all rhubarb recipes. On the savory side it is earthy and sourer than rhubarb so pickling is a good option. Save the tender shoots and try grilling, like with asparagus.
This fall, remember locations where you see knotweed flaunt its white plumes, and return in early spring to harvest tender shoots less than 10 inches tall.
It’s important to note that when you harvest knotweed you must not leave any loose remains of the plant behind because it can establish roots—or worse, drift to another area and root. In the kitchen, boil all peelings and leaves before discarding. This is mostly why it is difficult to control spreading.
Locally, I became aware of knotweed in the mid-nineties and have been trying to convert chefs ever since. Plenty of folks now think eating an invasive is a way to control it. Inspired by the University of Vermont there is even an Eat the Invaders movement in Burlington and a website that shares recipes.
I also suggest we ramp up the culinary aspect in Vermont by having culinary competitions on how to eat knotweed and other edible invasives. Vermont’s Junior Iron Chefs can stage recipe contests, promote the execution of the winning recipes, serve them at fundraiser dinners—and then—well, compete against New Hampshire…
Knotweek recipes:
After cooking, knotweed should be put through a sieve for use in cakes as well as in the following recipe for Knotweed Ice Cream by Vermont chef Ted Fondulas of Odyssey Events. In this recipe the sour sharpness of knotweed balances nicely with the rounded palate feel of cream. Knotweed doesn’t go far—at least on the dish—so pick and prepare enough of it to purée and freeze for winter use.
Knotweed Chutney
Makes 2–3 cups
Ingredients
- ¼ cup diced onion
- 2 cloves garlic, peeled and minced
- 1 cup knotweed, cleaned, chopped into small cubes
- 4 tart apples, peeled, cored, and cut into small cubes
- 1½ cup Vermont apple cider vinegar
- 1 cup Vermont sweet apple cider
- 1 cup white sugar or ¾ cup Vermont honey
- 1 teaspoon fennel seed
- ¼ cup dried currants
- ¼ cup onion, diced
- 1½ tablespoons ginger, minced
- ¼ teaspoon red pepper flakes
- ½ teaspoon yellow mustard seed
Directions
- Sweat onion and garlic in a saucepan.
- Add knotweed and apples.
- Sweat for 3 minutes.
- Add remaining ingredients.
- Simmer 30 minutes and check for desired thickness.
- Refrigerate or hot pack.
Knotweed Ice Cream
Makes 1 quart
Ingredients
- 1½ cups cleaned and chopped knotweed (peel if necessary; see “Preparing knotweed” below)
- 4 cups half-and-half
- 4 large egg yolks
- 1 tablespoon vanilla extract
- ½ cup sugar (see “Making it keto friendly” below)
- ¼ teaspoon xanthan gum
Directions
- Add knotweed to half-and-half and bring to a boil over medium heat. Turn off heat. Cover.
- Let steep 1 hour.
- In a bowl combine and whisk eggs, vanilla, sugar, and xanthan gum.
- Temper the egg mixture by slowly whisking in a little of the warm mixture. Then add remaining.
- Return to pot and place over low heat.
- Bring the mixture to 170 degrees or until it’s thick enough to coat a spoon.
- Strain with a fine sieve into a container. Cover with plastic wrap and refrigerate overnight.
- Place the ice cream maker bowl in a freezer; freeze overnight.
- The next day, using the cold mixture, follow directions provided by the ice cream maker.
Preparing knotweed
Knotweed is best when picked under 10 inches tall. When larger, the outside layer is woody. Much like asparagus, peeling is helpful. The leafy greens should not be used and should be boiled before discarding to prevent further spreading. The plant is fibrous, so straining through a fine sieve in necessary.
Making it keto-friendly
For a keto-friendly ice cream, use the same amount of Swerve in place of sugar.
Linda Santucci Fondulas’s company, Odyssey Events, has a long history with event planning in farm to table, weddings, and in wine/culinary educational tours they call odysseys. From world-class art in private estate venues to a simple in-house class, from full-scale destination weekends to a one-night pairing, they make party memories at your place or theirs. Visit http://www.odysseyeventsvt.com.
