Elaine Zmuda
Introduction
1 Infrastructures of Invasion
2 Species
3 Notes on Foraging with Care
Recipes
4 Asian Clam
5 European Green Crab
6 Garlic Mustard
7 Japanese Knotweed
8 Wild Chevril
What constitutes an invasion? The word has been applied widely to any arrival of unwanted people, animals, and plants. Invasion implies ill intent, harm, and destruction.
This is never the case with invasive species - no flower or crab shows up with the goal of destroying an ecosystem. They were not even in control of their journey to a new land - often they are accidental stowaways in ship’s ballasts or ride along with other natural products. These animals and plants are simply acting upon their biological drive to continue life and reproduce. The problem arises when their reproduction negatively affects their new habitat. With no natural predators, they are able to out-compete other species and dominate formerly diverse ecosystems.
Invasive species are a product of a more connected world. We see them appear with waves of new trade, immigration, and even trends across time. Historically, it took significant effort to move a plant or animal across the world. As globalization began to collapse time and distance in the 16th century, the nascent invasive was ready for its global debut. When we look at a map of everywhere the European Green Crab is today, we see how distant habitats may be more similar than expected. Boston, Nantes, Melbourne, and Seattle all support the crab’s life. What other connections can they expose?
When colonists first came to the US, they did not adjust to their new surroundings but reshaped them to become more familiar, more like their homes in Europe. Grain, the basis of our diet even today, could be considered an invasive species. It has taken over much of America. We don’t consider it as such because humans have complete control over it, but would the original prairie plants and animals see it the same way? Perhaps ‘invasive’ implies an outlook as opposed to an objective category. Garlic Mustard, considered an invasive today, arrived with early colonists as a medicinal herb. Now, it carpets forest floors across the country and has “no value.1” While it does compete with native wildflowers in some areas, especially sunnier regions, it has found a niche in other areas where few green leafy plants grew before. It, like many other invasives, thrives in the ruined landscapes industrialization and capitalism has left. Is it invading these landscapes?
1. “Garlic Mustard,” National Park Service Bailey, “An Overview”
Or is the coal mine the invasion? Like grain, Garlic Mustard and the other invasives in this book, is edible (although not the basis of an entire diet). We seem to have forgotten its use, what made it so important as to carry it on a dangerous journey across the world, and now only see its harm.
Early invasive species, like Garlic Mustard, required care to make their way across the world. We intentionally brought them with and cultivated them upon arrival. As the speed of trade increased and ship technology changed, more species were able to ride along without awareness on our part (or theirs). Beginning in the late 19th century, ships began using ballast water for stability and maneuvering control2. Before any regulation was put in place, ships would fill up their ballast at one port as needed and dump at their destination. Quite literally, they were mixing ecosystems. Many species unintentionally went along for the ride, including small crustaceans, fish, and mussels.
Referring to the arrival of new species as an ‘invasion’ reveals fear. Fear it will destroy an ecosystem and alter it beyond recognition. Fear we will lose desirable native (or ‘good’ exotic) plants and animals. Fear of a negative change in general. While these are all outcomes, some of which are happening already, it is not the entire story. Invasives can show us another way of looking at the world. They are tough, surviving long journeys, thriving in ecosystems that evolved without their needs. They carry histories of other places, flavors from around the world, and hints of different environments. As the world globalizes and heats up, they continue to prosper, despite our best efforts to remove them.
Another mindset would be to view them as potential. The ecological future of the world is becoming increasingly uncertain. With the changes that are expected to occur due to climate change, many dense centers of population will become unlivable, spurring even greater global movement. Plants will also migrate to escape nonviable conditions. Life will be in a rapid state of re-adjustment, of learning to live in new, unfamiliar environments, even if they are in the same physical location as previously. Our invasive species excel at this, surviving against the odds. Their fortitude can be a model for all of life. Rather than see them as strange and unsafe, we can start to look at them as cosurvivors. As they continue to flourish, they provide us food and a way forward. We can recognized their history as our history, one of a species striving for survival, finding it in the most unlikely of places with relations that span the globe.
2. Bailey, “An Overview”
Asian Clam Corbicula fluminca
European Green Crab Carcinus maenas
Garlic Mustard Alliaria petiolata
Wild Chervil Anthriscus sylvestris
Japanese Knotweed Reynoutria japonica
Foraging is one of humanity’s oldest skills. Wild plants enrich our diets, expanding our palette beyond the standardized tastes of the supermarket. Foraging requires situated knowledge, gained over time by dedicating oneself to repeated visits. It may be a solo activity, but it is always part of a larger community and ecosystem. Respect is essential. When going out to forage, especially for species considered invasive, keep in mind the following:
• Consider what permissions you need to enter the land. Question if the invasive asked this before it took root.
• Be certain of what you are picking. This book contains images to help identify plants, as do many others. It is always better to go with someone who knows what they are doing and share knowledge.
• Pull up the roots of the plant and quickly bag to minimize the spread of seeds. Baskets are great for carrying larger plants.
• Usually, foragers take only what they need. But if you are trying to eradicate an invasive species in an area, try taking a lot more than what you need. Transform the plant into a dish to share with others for a taste of what they are missing.
• Share your knowledge. Many foragers keep their favorite spots secret. There is no reason to not share where invasives grow. They are everywhere. If someone asks, direct them straight to the largest stand you know. On the map to the right, I share my spots that I have found during my short time in Cambridge/Somerville. There are many more almost anywhere you look once you get out.
Alewife Nature Preserve: near the entraces are huge stands of garlic mustard
Middlesex Fells: a great spot for a day of foraging a variety of species
Somerville Community Path: a variety of plans are found along the path. Make sure not to pick from the neighborhood gardens
Harvard University Campus: look in back corners, unused areas - the grounds crew touches these the least. Along some houses near campus, you can find Japanese Knotweed or Garlic Mustard
Charles River Path: focus near Alston
Asian Clams originate in Southeast Asia, spreading across the region’s estuaries and rivers from southern China through Indonesia. They first appeared in the Americas in the late 1920s, intentionally brought over by immigrants as a food source to remind them of home. As with many exotic species, they eventually escaped from their enclosures and made their way across the country through boating, spread in rivers, and intentional introduction. They were also sold commercially as bait for fishing (and may still be in some areas). Some pet stores have even re-branded them as Pygmy or Gold Clams for recreational sale. Today, they are found along both coasts, flourishing in cooler waters on the east coast.
The clams flourish in quiet waters with low salinity and sandy substrates. Sunny waters near the shore provide idea conditions, where they can partially burrow, but still receive enough light. This also makes them easier to harvest when compared with other, deeper-water species. They are relatively small, averaging about 1.5 inches in width. They are light green to brown with elevated concentric ridges. When opened, they have two lateral teeth and three cardinal teeth inside their shell.
The Asian clam is competitive and quickly overtakes new habitats where it is introduced. By exponentially increasing the amount of filter feeders in an ecosystem, they completely alter the environment and food chain. They form heavy clusters that cover the marine floor and may destroy marine infrastructures and vehicles. Other native mussels and clams struggle to compete with them.
Source: USGS, Smithsonian Environmental Research Center Nemisis
Asian clams were brought over intentionally to carry flavors of home. Their physical form mimics the suitcases that carried them over and offer a way to carry forward new flavors.
1 cup white wine
24 Asian Clams, cleaned
2 tbs EVOO
2 tbs unsalted butter
1 cup diced yellow onion
½ cup diced celery
¼ cup diced red bell pepper
2 cloves garlic, minced
1½ cup panko breadcrumbs
1 ts Worcestershire
½ ts red pepper flakes
2 tbs chopped parsley, divided
1 tbs chopped chives
Kosher salt, as needed
Freshly ground black pepper
Lemon wedges, for serving
1. Add the wine to a large pot and bring to a simmer over medium heat. Put clams in the pot and cover and cook them until they pop open, about 6 minutes Remove and let cool.
2. Once the clams are cool, remove the meat and chop. Set aside the meat in a large mixing bowl. Clean 24 halves of the clam shells and arrange on a baking sheet or in a casserole dish.
3. Heat a large skillet over medium heat. Add the oil and heat through, then add the butter. Once the butter is melted, add the onion, celery and bell pepper, sautéing until tender, about 5 minutes. Add the garlic and sauté until fragrant, about an additional 30 seconds.
4. Remove from heat, then stir in the breadcrumbs, Worcestershire, red pepper flakes, 1 tablespoon of the chopped parsley, chives and chopped clams. Add 1 cup of the clam juice cooking liquid, stirring to combine until the mixture holds together. Season with salt and pepper.
5. Heat oven to 350ºF. Use a spoon to stuff the cleaned clam shells with the breadcrumb and clam mixture.
6. Bake the stuffed clams until the tops of the stuffing are golden brown, about 25 to 30 minutes.
7. Move the clams to a serving platter, then garnish with parsley and lemon wedges. Serve immediately
Asian Clams are typically found in very dense bunches along the shoreline and in shallow water, making them relatively easy to gather. They can be easily substituted with native clam or mussel species. Research to make sure native you find are edible and not protected from foraging!
Gloves
Search during low tide, digging near holes in the sand. Asian clams will typically be partially buried in large clumps
Clamming Basket and Float
Wading Boots
Clamming Plunger and Net
Clamming Rake
The European Green Crab is one of the most invasive marine species in the world, having traveled around the world before ballast water was even known to carry species. They appeared in the northeastern United States in the late 1800s and have expanded their range around the world since.
European Green Crabs are small, typically about 10cm wide. They may be green, but they are also know to be brown and yellow. The easiest identification is to count the five spines/ points on either side of their eyes. Pre-molt crabs, the ideal stage to forage for, have a subtle color change on their lower abdomen and appear creamier. They will feel softer. A crab that has just molted will be very shiny green or lemon with purple claws.
Green crabs live on rocky shores, cobble beaches, sand flats and some tidal marshes. Typically, they will be found near the edge of vegetation, where they may blend in and find prey more easily.
There are few predators for the European Green Crab in the United States. They are aggressive hunters, even eating other crabs and young salmon. Their Latin name, Carcinus maenas, means “raving mad crab,” suggesting how humans feel about the crabs’ aggression, even where they are native.
Their preferred habitat, the edges of vegetation, is the spawning ground for many other species. Their destruction of grasses and other cover plants disrupts the reproduction of neighboring species, quickly decimating populations.
eyes
cm
Ballast water in ships carry marine environments around the world, depositing them in new homes when they arrive in foreign ports. It is the perfect soup for species to simmer into invasives. This ballast broth is able to convey any flavor you desire as well!
4 tbs olive oil
2 bunches celery with leaves, roughly chopped
1 large red onion, roughly chopped
1 small head fennel, cut into 1/2” slices
12 corn cops (optional) salt
1 tablespoon desired seasoning (optional)
3 quarts of water
2 cups white wine
2 dozen green crabs
1. Rinse crabs well in cold water. Leave in bucket with water until sock is boiling
2. In a large stock pot, heat oil to medium. Add the celery, onion, and fennel. Lower heat and cook until vegetables are soft (15 min). Add corn cobs, salt, and seasoning. Stir to coat vegetables and cook for 5 minutes.
3. Add water and wine, bring to a boil. Simmer for 10-15 minutes.
4. Bring back to a boil. Place crabs into boiling broth.
5. Cook at a strong simmer for 45 minutes. Cool and spoon out the cooked crabs and vegetables. Strain liquid through a cheese cloth.
Crabs are not required to be freshly molted for this recipe, although it will help to create a stronger flavor. They can be easily substituted with any other crab, invasive or native.
Crab trap with a pull line and float
Pre-molt crabs have a creamcolored underside
Recently molted crimes are bright green with purple claws
Garlic Mustard was introduced by colonists as a medicinal plant. It was first observed in the wild on Long Island and has since escaped. Its medicinal use has been replaced with modern pharmaceuticals, rendering it “useless” in modern society.
Garlic Mustard is a biannual plant, meaning it has a two-year growing cycle. During the first year, leave are rounder and grow in a rosette formation. Typically, it stays low to the ground. During the second year, the plant grows tall and flowers. Its leaves are more triangular or heart-shaped with toothed edges. Flowers are white with four petals. Seeds in the flowers can be harvested for spice. In either year, the leaves smell like garlic when crushed, making it easy to identify.
Garlic Mustard is found in forests in Europe, but in the United States, it is found almost everywhere, from forests, roadsides, creek edges, and urban space. It can grow in both shady and sunlight areas. It should ideally be harvested before seeding so they do not spread during the harvesting process. The younger the plant, the less bitter it will taste. Pulling after rain make it easiest to remove the full plant and root. They should be bagged quickly after harvesting.
Like the colonists and settlers that brought Garlic Mustard to the Americas, it has wrecked havoc on the ecosystems it has taken route in. It thrives in the destroyed landscapes, in northeastern forests that were cut down and then abandoned, along old road edges, and in vacant lots. It easily dominates the forest floor, creating conditions where native species cannot grow, changing the ecology.
toothed, triangular leaves
rounder lobed leaves
grows lower to ground
small white flowers
year 2
year 1
Garlic Mustard was originally brought over by colonists for medicinal uses and flavoring food. It grows early in the season, as if it is trying to take care of us right at the moment everyone catches a cold. These recipes offer different ways to take advantage of medicinal properties of garlic mustard, including providing relief for a common cold and sweating out a fever.
dried garlic mustard leaves
vodka
olive oil
Tincture:
1. Macerate dried garlic mustard leaves in vodka for 4 - 6 weeks in a cool, dark space
2. Remove the leaves, strain vodka through a cheesecloth
Tea:
1. Crush dried garlic mustard leaves into a powder
2. Steep in boiling water for 5 - 10 minutes
3. Strain out powered leaves
Oil:
1. Infuse dried leaves in olive oil for 2 - 3 weeks
2. Remove leaves from oil
3. Oil can be used on skin or added to food
When harvesting garlic mustard leaves, be careful to minimize the spread of the plant. Bag plants immediately so seeds to not disperse when walking.
make sure all equipment is sterilized before using
dry the leaves in the sun for a few days or in an oven
try to harvest entire plants. carefully gather in a basket
Japanese Knotweed was introduced to the United States in the late 1800s for ornamental planting. Due to its size, it was popular for privacy, as it quickly grows large and dense. It is native to countries in eastern Asia, including Japan, China, Korea and Taiwan.
Japanese Knotweed is a flowering plant that grows in a bush-like shape. Near the base, it stalks are similar to bamboo. Branches and stems area reddish color, similar to rhubarb (which it also tastes like). To confirm, snap off a stem and check if it is hollow. The leaves are dark green. At the end of the summer, each stalk flowers, with dense clues or white blooms. In the winter, stalks fall off and sprout new plants, aiding in its rapid spread.
Outside of gardens, Japanese Knotweed is found in previously disturbed land. Roadsides, trails, and vacant lots provide enough light and exposed topsoil for easy and rapid growth.
Japanese Knotweed grows incredibly fast and dominated other species by its sheer size. It can reproduce through multiple means (seeds, rhizomes, cuttings, pollination...). It is a mineral-hungry plant, depleting soil for its neighbors. Because its original habitat was in volcanic soils, it can handle most any conditions. It is strong enough to grow through concrete and asphalt, easily adapting to tough urban conditions where little else thrives.
small white flowers
reddish stems
Mousse
Japanese Knotweed was popular during the Victorian Era and imported as an ornamental plant. It quickly escaped from gardens and is found all over. Although invasive because it out-competes native species, it adds an element of unexpected beauty.
5 cups Japanese knotweed stems
3/4 c sugar
water
4 leave gelatin OR 1.25 tbs powdered
3 eggs whites whipped until stiff with 1/8 c of white sugar
2 tbs chopped wild peppermint
(optional)
Peppermint leaves and flowers to garnish
1. Gather stalks with thick stems. Wash and remove all leaves and tips.
2. Slice into 1” pieces, put in a pot, add sugar. Let stand 20 minutes to extract juices
3. Add about 1/2 cup of water, and cook until pieces are soft. Add more water if necessary to keep from scorching. Cool.
4. Puree knotweed with lemon juice or more sugar to taste.
5. If using gelatin leaves, bloom in ice water until soft.
6. Gently heat knotweed puree, then whisk in gelatin until dissolved.
7. Chill mixture, then whisk.
8. Fold in the beaten egg whites and wild mint. Chill again until ready to serve
9. Add peppermint leaves and flowers to garnish
When stemming and trimming knotweed, do not compost leaves immediately. Heat them in a microwave to kill the plant so it does not spread further. When harvesting the plant, the only way to remove it completely is to rip its roots and rhizomes out. After, make sure to bag the plant quickly so it does not spread seeds.
scissors and knife to trim shoots
flowers for garnsih
Wild Chervil is a flowering plant originally from Europe, similar in appearance to Queen Anne’s Lace. It came over in wildflower seed mixes from Europe for use in gardens, and quickly moved beyond enclosed yards.
Wild Chervil looks similar to many other wildflowers found in the US. It is technically a flowering herb, similar to parsley. It grows up to about four feet in height, typically in dense stands. Stems and leaves have small hairs. Leaves are fern or lace like, with complex leaves. This is the easiest way to distinguish it from other non-edible plants. A leaf is comprised of 3-5 leaflets. Each leaflet is further subdivided into 3 pinnates per leaflet (see the image on the right). In June, clusters of small white flowers bloom in larger groups, or heads.
Wild Chervil tolerates a variety of soil conditions, both wet and dry. It it typically found in sunnier areas, especially at the edge of wooded areas.
Wild Chervil is found in many places other invasives appear, but it is particularly damaging to wetlands, where it interrupts the delicate balance of the ecosystem. It also appears in many pastures and it eaten by cows (hence its other name, Cow Parsley). It is safe for cows and other herbivores to consume, but it lessens the variety of grasses they eat, limiting the nutrients they receive.
small white flower clusters
stems may have small hairs
fern-like leaves, typically with 3 pinnates per leaflet
Chervil was brought over in seed mixes of European wildflowers. As it typically mixes with other species, this recipe is a cross-over, made with both Wild Chervil and Garlic Mustard, as well as other ingredients for a diverse wild flavor.
5 cups lightly packed garlic mustard leaves and tips, loosely chopped
5 cups lightly packed chervil leaves, loosely chopped
1/4 cup pine nuts
1 garlic clove, peeled and roughly chopped
1/3 cup grated Parmesan cheese
1 cup extra virgin olive oil
1/2 teaspoon salt
1/2 teaspoon sugar, optional
2 squeezes lemon juice
1. In a food processor or blender, blend the garlic, pine nuts and Parmesan
2. Add the garlic mustard and chervil leaves
3. Begin blending again. Add a steady stream of olive oil until smooth
4. Stir in the sugar, salt, and lemon juice and pulse until blended
Wild Chervil and Garlic Mustard are incredibly common, as well as many other edible plants like wood sorrel and chickweed. Any can be mixed into this pesto for new flavors. Basil, the standard pesto herb, can also be incorporated. When harvesting, take care to not disturb flower heads - they will disperse seeds. Be very careful when identifying - it looks similar to many other inedible species.
italian parsley basil
chickweed
wild chervil
garlic mustard
wood sorrel
Chervil spread through European seed mixes. Be sure not to spread any seeds when foraging
Foraging passes on knowledge from many sources, often through quick conversations and word of mouth. The sources here incorporate a similarly diverse mix. Academics write about histories of shipping, artists consider Japanese Knotweed’s real estate, chefs share secret ingredients, and homesteaders use nature to throw off the shackles of government. Invasive species span these strange bedfellows and more. We all interact with these visiting species and all have something to learn from them.
Alaska Regional Office, “Look Out for Invasive Crab!” NOAA Fisheries. Updated Jan. 26, 2023. Accessed May 1, 2023. https://www.fisheries.noaa.gov/alaska/habitatconservation/look-out-invasive-crab#:~:text=Green%20crabs%20were%20first%20 introduced,in%20ballast%20water%20as%20well.
Baily, Sarah A. “An overview of thirty years of research on ballast water as a vector for aquatic invasive species to freshwater and marine environments.” Aquatic Ecosystem Health & Management. Vol. 18 (3): 261 - 268. https://doi.org/10.1080/14634988. 2015.1027129
Bergo, Alan. “Knotweed Mousse.” Forager Chef. Updated Dec. 3, 2022. Accessed May 1, 2023. https://foragerchef.com/wild-rice-knotweed-mousse-roulade/
Cameron, Sophia and Jesse Wheeler. “Invasive Plant Profile: Japanese Knotweed.” National Park Service. Accessed May 2, 2023. https://www.nps.gov/articles/000/japaneseknotweed-acadia.htm
“Corbicula fluminea.” Nemesis (Smithsonian Environmental Research Center). Accessed April 8, 2023. https://invasions.si.edu/nemesis/species_summary/81387
Cooking Sections (Alon Schwabe and Daniel Fernández Pascual), “The Next Invasive is Native.” in The Empire Remains Shop, ed. Cooking Sections, 159 - 187. New York City: Columbia University Press, 2018.
“Garlic Mustard.” Mayernik Kitchen. Accessed May 2, 2023. https://www.mayernikkitchen. com/medicinal-plants/garlic-mustard
“Garlic Mustard.” National Park Service. Updated Feb. 26, 2015. Accessed May 3, 2023. https://www.nps.gov/blue/learn/nature/garlic-mustard.htm#:~:text=This%20 invasive%20plant’s%20native%20range,any%20value%20(Miller%202004).
Gabriela Bradt and Marissa McMahan. The Green Crab Guide: In the Field & In the Kitchen, (University of New Hampshire), Accessed May 1, 2023. https://unh.app.box.com/s/ xw5syngpnenvem742pnf0pnttgm5dysj
Kling, Andrew. “Invasives in Your Woodland: Japanese Knotweed.” University of Maryland Extension. Updated May 4, 2022. Accessed May 3, 2023. https://extension.umd.edu/ resource/invasives-your-woodland-japanese-knotweed
Mazon-Chambers, Kylie. “Stuffed Clams Recipe.” Cooking with Cocktail Rings. Updated Dec.19, 2021. Accessed April 10, 2023. https://cookingwithcocktailrings.com/stuffed-clams-recipe/
“NAS - Noninidgenous Aquatic Species.” US Geological Survey. Accessed April 8, 2023. https://nas.er.usgs.gov/viewer/omap.aspx
“Wild Chervil (Anthriscus sylvestris).” Vermont Center for Ecostudies. Accessed May 3, 2023. https://vtecostudies.org/projects/grasslands/new-england-grassland-bird-initiative/ wild-chervil/
“Wild Chervil.” Mass Audubon. Accessed May 3, 2023. https://www.massaudubon.org/learn/ nature-wildlife/invasive-plants/wild-chervil#:~:text=Wild%20chervil%20(Anthriscus%20 sylvestris)%20is,up%20to%204%20feet%20tall.
“Wild Edible: Japanese Knotweed.” Hillsborough Homesteading. Accessed May 3, 2023. https:// hillsborough-homesteading.com/wild-edible-japanese-knotweed/