Japanese knotweed shoots. Credit: Courtesy David Spahr

Move over locavores, there’s a new way to eat sustainably as an invasivore.

As the term implies, invasivores consume invasive species. Doing so helps reduce invasive species on the Maine landscape that threaten native plants and terrestrial or aquatic animals.

There are hundreds of invasives in Maine, but not all are edible and the likelihood of eating any of them into extinction is remote. But that doesn’t mean it’s not worth knoshing on a plant that threatens important crops or a native fish population.

Some of these invasives are tasty.

“I’m a big fan of eating autumn olives,” said Robert Dumas, food science innovation coordinator at the University of Maine. “They are an invasive [species] you find on the margins of fields.”

Autumn olive (Elaeagnus umbellata), also known as Japanese silverberry, is considered a noxious weed. Blueberry growers, in particular, struggle to control it. It’s also somewhat of a super food, containing high amounts of Vitamins A and C, carotenoids and lycopene.

The shrub can grow as high as 20 feet and has alternate long, oval leaves that are dark to grayish green on top and have silvery white scales below. Autumn olive flowers are light yellow and small. The berries are less than a quarter-inch and ripen from yellow to pink to red.

Steamed, Japanese knotweed is the best of both worlds for fiddlehead and asparagus fans. Photo by Fia Fortune

“They are prolific berry producers and those berries are the size of a TicTac,” Dumas said. “I think they have a flavor similar to a sour gummy worm — sweet and tart.”

Autumn olives spread by way of birds, which consume the berries and deposit seeds randomly in their droppings. Cutting back the shrub also encourages it to grow back even larger.

While Dumas is not about to share his prime autumn olive foraging spots, he did say they are found on a lot of state-owned land at the margins of fields and clearings.

Dumas also enjoys a nice serving of the invasive Japanese knotweed (Fallopia japonica), also called Mexican bamboo. It grows all over Maine along rivers and lakes, edges of forests, disturbed forest areas and open uplands. The green leaves are quite large and heart-shaped. Small clusters of white flowers bloom in late summer and early fall and the stems are hollow and bamboo-like.

The time to eat knotweed, according to Dumas, is early spring when the young shoots are tender and have a taste comparable to rhubarb.

“I like to sliver them and eat them raw,” Dumas said. “They have a tart, lemonade flavor that pairs really well with strawberry.”

In particular, Dumas is a fan of strawberry-knotweed jam.

The plant is also a favorite late summer food source for honey bees and produces a dark, molasses-like honey, according to Dumas.

Maine waters are also sources of some edible invasives.

Along the coast, populations of the invasive European green crab are exploding, creating havoc with fisheries and outcompeting native shellfish species.

Considered a delicacy in other parts of the world, green crabs have not quite caught on here. They are small and extracting the meat is labor intensive. The meat, when cooked, is described as mushy.

Denise Skonberg, professor of food science at the University of Maine, has been working with green crabs in her lab for close to two decades. She’s studying how the crustacean can be turned into a value-added food product like fermented green crab sauce.

Hundreds of miles inland and to the north, the invasive and aggressive muskellunge — commonly called muskie — swam into the St. John River watershed from Quebec in the 1970s. Since then the fish has decimated local native brook trout and landlocked salmon populations.

They can grow to more than three feet in length and are considered a prize sport fish in the Midwest. That’s why every year hundreds of people take to boats and canoes in late summer for the annual Fort Kent Muskie Derby.

The Department of Inland Fisheries and Wildlife wants them gone so badly there are no size or bag limits on muskies during open water fishing season.

Highly prized for its firm, white meat, a muskie filet served with butter has been compared in taste to lobster. It’s also great for making fish and chips and as the main ingredient in a chowder.

When it comes to being a practicing invasivore, it is important to keep in mind that not every invasive is edible.

According to Gary Fish, state horticulturist with the Maine Department of Agriculture, Conservation and Forestry, many are not. And, as far as he knows, there is not a high demand for those that are.

“I don’t think it will ever be a way to control a species,” Fish said. “It may help reduce their overall impacts, but only if the level of harvest is pretty intense and the markets boom.”

Fish are also aware of interest in invasives beyond plants.

“I have also heard of doing this with beetles and such,” he said. “But again, not sure people will ever develop a liking to eating these things.”

Dumas, for one, is ready to give it a try.

“I’m working up the courage this year to eat Japanese beetles,” he said. “My understanding is they take up the flavor of whatever you put on them.”

Anyone who grows anything in Maine knows about Japanese beetles. The grubs feed on the roots of grass, damaging lawns and pastures. The adult beetle eats the foliage, flowers or fruit of more than 300 different Maine ornamental and agricultural plants.

“You can harvest them right off your prize raspberry bushes,” Dumas said. “Then you need to drop them in a jar of water so they purge out whatever plant they have been eating.”

From there, the beetles can be frozen, parboiled, toasted or dried.

By weight, the Japanese beetle has the same amount of protein as a sirloin beef steak. They are also high in vitamin B12 and zinc.

“I am going to try to make protein-packed trail snacks with them,” Dumas said. “I have no shortage of those little buggers.”

Dumas views insects as the next food frontier.

“I’m willing to experiment in that direction,” he said. “If you eat shrimp, you are just eating an ocean bug, so why not?”


Julia Bayly

Julia Bayly is a reporter at the Bangor Daily News with a regular bi-weekly column. Julia has been a freelance travel writer/photographer since 2000.