Mad, bad and dangerous to know: Cooking with the invasive plants in your backyard

This is the second of a two-part story on invasive species by Andie Bulman. Bulman explored aquatic species in Part One, which you can find here.

Purple loosestrife pops up in Conception Bay South, Japanese knotweed surrounds downtown St. John'sand stinging nettles march into meadows and barrens.

Invasive alien plants are everywhere. You'll find them in fields, forests, and in your backyard. The good news? We can eat some of them, and it's a practice many horticulturists encourage.

Tim Walsh, nursery manager and horticulturist at the Memorial Botanical Garden, is all for this growing trend.

"There's been a significant shift towards eating local, and an interest in foraging is something we hear about at the Botanical Gardens all the time," Walsh said.

But there are some rules people should follow, hewarns.

"Go slow, as some plants are diuretics, and your body needs to get used to them. Learn from experts, and buy good guidebooks. If you do that, I think eating these edible invasive alien species is an excellent idea."

Some scientists are hesitant about the "eating the invaders" approach, though,concerned that these species could be reimagined as a commodity. Still, Walsh doesn't think the desire for these plants will ever be that strong.

"I don't see farmers planting fields of invasive alien plants to try and meet the demand, and these plants have already established a population here, so why not enjoy the free food that invasive alien species provide?"

Invasive alien plant species grow aggressively, taking over space, choking out their neighbours; within a short time, they've out-produced the other plants and have created a monoculture.

"These plants, when growing back in their native habitats, had controls that limited their growth," says Walsh. "Maybe a predator kept the population in check, or perhaps something about the climate kept the population under control. But without those checks and balances, these plants can now thrive and out-compete other native plants."

Japanese knotweed is one of the worst offenders. It has a solid root base and becomes a long, spreading plant that shades smaller plants. Growing in thick, dense colonies, you can find it in almost every town and bay in Newfoundland.

"There's no biodiversity when knotweed takes hold. Our advice at the gardens is to grab it and take it out by the root when you see it. Don't wait until tomorrow."

Most of the plant invaders in Newfoundland made it here through human activity. Ballast waters, which are responsible for some of our aquatic invaders, can carry seeds. Other species can be traced back to garden centres and nurseries.

"Goutweed, an edible invader, was sold as ground cover. And we know that knotweed was brought to North America for erosion control. The intentions were good, but plants like knotweed cause ecosystems to lose their diversity. We'll never be able to eat enough of it," says Walsh.

Finally, some species end up here through a weird combination of happenstance and economy. Although it's not considered an invasive, edible species, you can find a beautiful, rare orchid in Tilt Cove.

"The southern marsh orchid has a population that has grown but hasn't displaced native vegetation, so we're not considering it an alien invasive," says Walsh, "but it is an interesting example of how seeds can travel. It's thought to have piggybacked in packing straw when some mining equipment was shipped to the area in the 1800s."

Islands,like Newfoundland, are at once more protected and more at-risk from invading species.

"Things may take longer to get here because of our physical separation from continental North America," Walsh says. "Once they are here, it is sometimes easier for the species to get established because of a lack of natural competitors and predators."

Cooking with invasive, alien plants

Foragers like Shawn Dawson of the Barking Kettle have been eating invasive species for some time.

"In the spring, I rarely go to the grocery store. I pick the invasive species at my doorstep, like knotweed and stinging nettles."

Dawson's been making a chutney with knotweed for years, mixing it with rhubarb and cooking it down with ginger, brown
sugar, and onions.

"Knotweed chutney is great on a cheese plate," says Dawson, "but I prefer to lacto-ferment it. It softens the sourness, but it still has a great bite."

Most chefs will agree that there's not too much to be done with knotweed as it ages. Later in the summer, it becomes bamboo-like and too fibrous to be of much use, but Dawson's had ceviche and cocktails made from its sour juice.

"There's probably lots you can do with fully grown knotweed.We just have to get creative and think outside the box," he says.

Another of Dawson's favourite invasive alien plants to eat is the stinging nettle, which also goes by the name "common nettle," or "burn nettle." Chock-full of vitamins, nettles have bright green, toothed leaves, and in some parts of Newfoundland, are an almost omnipresent plant.

"You make pestos and soups with nettle," says Dawson. "It's delicious, but you need to handle it correctly. Wear gloves, blanchit before using (this takes out the sting), and then enjoy. Out of all the invasive plants, it's probably the tastiest."

Lacto-fermented Japanese knotweed

Recipe makes onequart. I often skip this step, but peeling the knotweed improves the texture!

Ingredients

• 1 cups young knotweed shoots, peeled, tips discarded
• 2 tbsp. of kosher salt
• 5 sprigs of dill
• 1 tbsp. of fresh thyme
• 3 strips of lime peel
• 1 bird eye chili
• 1 tsp peppercorn

Instructions

1. Cut the shoots into three-inch pieces, toss with the remaining ingredients save for the water and salt, and pack into the quart jar. Mix the salt and water until dissolved, then pour over the contents of the jar.

2. Screw on the lid(s) and leave on your counter, opening the jars occasionally to burp them. Burping is a significant word and concept in the fermentation world. It means opening your lid for a brief period of time, so your air can escape, then tightening it back up. If you don't "burp" your fermenting jars, well, the thing could erupt. I just do it for about a minute here.

The knotweed pickles will begin to sour after three days in the brine at room temperature. I like to move them to the fridge. I like these whole on a cheese plate, or you can slice em' up and use them in a grilled cheese.

Stinging nettle pesto

Recipe makes a medium-sized mason jar.

Ingredients

• 3 garlic cloves
• 2 tbsp. toasted sunflower seeds (you can use pine nut if you're feeling wealthy)
• 2 tbsp. parmesan
• cup blanched nettles
• Salt to taste
• Good olive oil

Blend garlic andsunflowers in a food processor, add grated parmesan, then add nettles, saltand drizzle in olive oil slowly. I like a chunkier pesto, but you do you.

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