It’s green, it spreads fast, and it’s not something every homeowner wants to find out they have. Japanese knotweed was back in the news this week after a clump of the plant growing in a west London garden led a home buyer to take his seller to court for not being open about the property’s tenant. But when I heard about him, I confess that my first reaction was lucky him!
Obviously the polygon is terrible if you have it in your house. It is considered one of the most virulent invasive species in the country and is nearly impossible to get rid of. But the knotweed is also delicious. As long as your clump hasn’t been injected with herbicide in recent years, it’s a superfood. I drank it in fruit fools and used it to infuse gin. At the Silo, a zero waste restaurant in east London, they serve it grilled in salads. It looks a bit like asparagus.
Japanese knotweed arrived in the UK in the 1800s, introduced as an ornamental plant from East Asia, where it grows alongside predatory insects and fungi in nutrient-poor soils, digging roots down meters deep and pushing through lava to reach the light. So it’s tough. Unfortunately this means that concrete and asphalt are no match for the lava destroying polygon and if you discover it on your land you will definitely want to check it out.
In spring, organic gardeners can be found judiciously digging up the young shoots that sprout from the ground; most burn what they’ve removed, but a few carefully pick up the weeds and head into the kitchen, making sure not to drop any of the plants along the way. Here they dispose of the plant in another way: by cooking and eating it.
It’s in the same plant family as rhubarb and wood sorrel, which might make eating it as an eradication strategy seem less puzzling. Not only does it taste like a cross between the two, but it’s also packed with minerals and vitamins. Knotweed has a long history of use in traditional medicines – with high levels of resveratrol, a polyphenol that supports heart and brain health – and is currently being tested for the treatment of tick-borne bacteria that cause Knotweed disease. lyme.
If you need more convincing to get out of a knotweed bush, look to East Asia, where it’s fermented or salted. This not only allows knotweed to be consumed later in the year, but also reduces the amount of oxalic acid in the plant which can cause kidney stones.
Eaten fresh as a spring vegetable, the young stalks are plucked when they are the size of pencils and sauteed, sautéed and even coated in a tempura batter, or grilled with a gooey layer of miso, soy, grated ginger and garlic , to give the fast growing shoots a delicious finish.
If fatty meats and oily fish are your thing, Japanese knotweed can help you with that, too: it makes a delicious mint sauce dressing when finely chopped with mint, fennel and dill, with a generous swig of sweetened apple cider vinegar and a pinch of salt and sugar.
The plant can happily swing between savory and sweet dishes. It cooks the same way rhubarb does, softening into tender strands that cry out to be mixed with curds and turned into a crazy fruit. If a silly sound like your way of dealing with the tuft, cook 450g of young chopped knotweed stems in a pan with the zest and juice of one lemon and 3 tablespoons of sugar and cook until tender. Leave the fruit to cool before mixing with 300ml of whipped cream and 100g of Greek yoghurt.
US foraging chef Alan Bergo recommends peeling the stems to remove any stickiness. He’s also a fan of pureeing the cooked stems, using the smooth mixture to make sherbets and mousses and dehydrating them to make fruit skins. A jar of cooked and smoothie marbled knotweed with vanilla custard, put back in the freezer for a couple of hours before serving and then garnished with crumbled meringue nests, makes for an easy and elegant dessert.
And it can be fermented into wine or pressed and added to cocktails as an acidic ingredient. Wild cocktail guru and foraging guide Mark Williams, of Galloway Wild Foods in Scotland, is an advocate of knotweed juice vodka cocktails.
And the knotweed is just as happy in a gin bath. To make knotweed gin, try filling a Kilner jar with 500g of washed and chopped young knotweed buds, 100g of caster sugar and 400ml of gin, either alone or with a couple of star anise or cardamom pods. letting them soak for four weeks before straining and drinking a victorious toast to your predatory skills.
Liz Knight is a wild food forager and chef and the author of Forage: Wild Plants to Gather and Eat, where you can find more recipe ideas for knotweed