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Invasive Species Spotlight: Foraging for Invasives

Invasive Species Spotlight: Foraging for Invasives

Autumn Olive (Elaeagnus umbellata). Pennsylvania Department of Conservation and Natural Resources - Forestry, Bugwood.org
March 1, 2020

With the start of spring comes the beginning of another season of the never-ending battle between conservation warriors and the pesky invasive plant species that have taken over our ground. The U.S. Forest Service defines “invasive species” as those that are non-native to the ecosystem in question and whose introduction causes—or is likely to cause—economic or environmental harm or harm to human health.

While invasive species can be any kind of living organism, this article focuses on invasive plant species (“invasive plants”) that have become an all too common sight in our local landscape. These plants have an enormous negative impact on our natural resources. They are aggressive and multiply quickly, outcompeting native plants for sunlight, space and nutrients. They are also a major threat to the biodiversity of our landscape, giving native plants little chance of survival without the help of human intervention. The removal of invasive plants is a crucial step to the protection of our native landscape. Unfortunately, this process can be overwhelming, requiring a great deal of patience and significant financial resources. 

Invasives on the Menu?

While there are many methods of dealing with unwanted plant species, some of them are actually edible and can make great additions to recipes. Foraging edible wild invasive plants is a free control method that can help allow native plants the chance to thrive once again. The idea of eating invasives, both plants and animals, has become popular in trendy restaurants, promoting sustainable consumption. Invasive species consumers have even gone as far as categorizing themselves as “invasivores.” While foraging wild invasive plants for consumption will not put a dent in large populations, it does make the task of invasive control within your own property slightly more pleasurable knowing you may at least get a tasty treat out of the ordeal.

The most important rule to follow when foraging any wild plant species for consumption is to be absolutely positive of the identification of the plant.This includes knowing exactly what parts of the plant are edible and the environment that the plant was grown in. Some species of plants have look-a-likes that can be tricky to tell apart. Researching the invasive plant you are foraging for and identifying key characteristics will often reveal noticeable traits to help differentiate. Another important rule is to be familiar with the environment from which you are foraging. For instance, you should know whether an area has been sprayed with herbicide or pesticide. In addition, you should not eat plants from areas that frequently flood—floodwaters can bring harmful chemicals and bacteria that can be soaked up through the plant. 

Tasty Invasives

Below are a few common invasive plants in our region that make a great snack. A quick internet search will reveal many recipes incorporating these invasive plant species.

Garlic Mustard (Alliaria petiolata)

Garlic mustard is an invasive biennial herb, growing its first year as a rosette stage plant, remaining green through winterand flowering the next year. It generally grows to be 3-feet tall with alternate, heart-shaped toothed leaves and 4-petaled white flowers appearing in clusters at the top of the stem in early spring. It is most often found within woodland understories or edge, floodplains or disturbed areas. 

Garlic Mustard (Alliaria petiolata). Photo by Chris Evans, University of Illinois, Bugwood.org
Garlic Mustard (Alliaria petiolata). Photo by Chris Evans, University of Illinois, Bugwood.org
Garlic Mustard (Alliaria petiolata). Photo by Richard Gardner, Bugwood.org
Garlic Mustard (Alliaria petiolata). Photo by Richard Gardner, Bugwood.org
For inexperienced foragers, you can’t go wrong with garlic mustard. It is easy to find, easy to identify and pretty much every part of the plant is edible. As the name may suggest, this plant is a member of the mustard family and adds a kick similar to the flavor profile of garlic. A strong sent of garlic when you crush the leaves is a dead giveaway that you have identified the correct plant. The age of the plant and the time of year in which you are harvesting the plant effects the flavor profile. Garlic mustard is most palatable when harvested young and should be eaten from early to mid-spring. The leaves tend to become bitter with age and the environment in which the plant has grown in can also affect the taste. Garlic mustard can be used in a host of recipes such as pesto, soups and salads. The roots can be pickled. The leaves can be dried and ground, like oregano. Seeds can also be ground into mustard. The leaves can be sautéed and used as a substitute for greens like spinach or collards. Add sautéed garlic mustard to omelets or a stir-fry. There are countless recipes out there on how to add this invasive into your diet. 

Wineberry (Rubus phoenicolasius

Wineberry is in the same family to which raspberry and blackberry belong. It poses a threat to native plants due to its aggressive nature, forming dense thickets and shading out surrounding natives. The arching stems can grow to 9-feet long and are covered in reddish hairs. This gives the stems an overall red appearance from a distance. Leaves are heart shaped with serrated edges, purple veins and a fuzzy underside. It prefers moist conditions and ample sunlight, often found along the edge of woodlands. Similar species include black raspberry and red raspberries. The good news: all species are edible and equally delicious. In late June/early July, the ruby red berries will reach peak ripeness. Turn wineberries into preserves, jams and sauces or use them in pies and crumbles. Berries can be frozen for future use. Or simplest of all, they make for a refreshing snack right off the bush.

Wineberry (Rubus phoenicolasius). Photo by Richard Gardner, Bugwood.org
Wineberry (Rubus phoenicolasius). Photo by Richard Gardner, Bugwood.org
Wineberry (Rubus phoenicolasius). Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Wineberry (Rubus phoenicolasius). Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Japanese Knotweed (Fallopia japonica

Japanese knotweed is an herbaceous perennial in the buckwheat family reaching over 10 feet in height. Leaves are oval-shaped and about 6-inches long with pointed tips. Sprays of greenish-white flowers begin to bloom in summer and are followed by winged fruits. Japanese knotweed primarily spreads by rhizomes. The spread of this species is aggressive, and it quickly forms dense thickets outcompeting native plants. It is a particular threat to riparian areas because it is well suited for flood zones. 

Japanese Knotweed (Fallopia japonica). Photo by John Cardina, The Ohio State University, Bugwood.org
Japanese Knotweed (Fallopia japonica). Photo by John Cardina, The Ohio State University, Bugwood.org
Japanese Knotweed (Fallopia japonica). Photo by Jan Samanek, Phytosanitary Administration, Bugwood.org
Japanese Knotweed (Fallopia japonica). Photo by Jan Samanek, Phytosanitary Administration, Bugwood.org
The taste of knotweed is often compared to rhubarb and can be used as an alternative in many rhubarb recipes. However, unlike garlic mustard, only certain parts of this plant are edible and only at certain times of the year. The shoots are the only part of this plant that is edible. Shoots are tender and ready for harvest in early spring, mid-April to May. Look for shoots about one foot tall or shorter. The stems become tough and woody if you wait too long. Eating knotweed raw is not suggested, as it has been known to cause skin irritation. Japanese Knotweed can be used in purees and jellies, pies and breads. It can be pickled and added to salads. When knotweed is cooked it becomes much softer and works well in curries and other creamy based sauces. 

Autumn Olive (Elaeagnus umbellata)

Autumn olive is a small perennial tree or shrub growing up to 20-feet tall. The species thrives in poor soils, fruits prolifically, and grows and spreads at an aggressive rate. Autumn olive has silvery scales on the bottom side of the leaf with smooth edges. The leaves are alternate, an important identification clue to differentiating the shrub from a few nonedible look-a-like honeysuckle species which have opposite leaves. Russian olive is another closely related look-a-like. The leaves of Russian olive are narrower and are silvery on both the top and bottom. The yellow to brown fruit of Russian olive are edible, however they are not very appetizing and have a very dry mealy texture. 

Autumn Olive (Elaeagnus umbellata). Photo by PA DCNR - Forestry, Bugwood.org
Autumn Olive (Elaeagnus umbellata). Photo by PA DCNR - Forestry, Bugwood.org
Autumn Olive (Elaeagnus umbellata). Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Autumn Olive (Elaeagnus umbellata). Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
After three years of growth, yellow flowers begin to bloom in June or July. Autumn olive fruits have matte red, round, juice-filled berries with white speckles, which are the only portion of this plant that is edible. While in the olive family, the fruits taste nothing like an olive. Many have found that autumn berries taste like a savory version of cranberries or pomegranates. Later in their ripeness they tend to become sweeter in flavor. The berries contain a small pit. While they are not harmful to eat, they are not quite small enough to comfortably swallow and ignore. The pulp of the berry can be used to make sauces and jams. Autumn berries make a great substitute in recipes that call for raspberries such as pies. They can also be a part of more savory options such as autumn olive ketchup and barbeque sauce. 

The Impact of Invasives

Highlighting invasive species as tasty and delicious is a double-edged sword. It is important not to minimize the detrimental effect that these species can have on our ecosystem. Eating invasive plant species into submission one meal at a time is an unrealistic goal. It will take a much more aggressive hands-on approach to really put a dent in these invasive populations. In the meantime, serving a garlic mustard pesto pasta with a wineberry pie for dessert could at least be a great way to engage and educate your dinner guests. This article may only list a few species, but there are many more out there to include on your next dinner-party menu. 

Citations: 

Pennsylvania Department of Conservation of Natural Resources

Southeast Exotic Pest Plant Council

U.S. Dept. of the Interior, National Park Service, Plant Conservation Alliance

U.S. Dept. of Agriculture, National Agricultural Library