Invasive Species Removal
When you look out across the landscape, a great number of the plants you see are non-native. Most of the roadside flowers and shrubs that you walk or drive past every day fall into this category. But many of these plants do not stay isolated along roadways and developments: they escape into the woods and other natural areas, stealing the food, water and sunshine our native plants need for survival. In other words, they become invasive.
Some of these aliens were introduced by accident, traveling westward with early settlers who brought them over from Europe – a little piece of home, or a source of familiar food or medicine in a land full of strange new plants. Others were introduced as ornamentals, decorative plants to make the landscape look a little more exotic. Still others were touted as the perfect food for wildlife and subsequently people were encouraged to plant them in great quantity. Years later, we discovered the then unknown problems these plants would create.
Working with a grant from the Michigan Department of Natural Resources, the Cut -n- Dab Society (our dedicated group of volunteers who meet weekly to tackle invasive species) is reclaiming an area along the Glacial Pond and north and west of the prairie. We are concentrating our efforts here because it is critical Eastern Massasauga Rattlesnake habitat. This snake has “Special Concern” status in Michigan, which refers to any wildlife species that may become a threatened or endangered species in the future. Workdays are Thursday mornings from 9:00 am to noon year-round. Please contact us with questions.
Invasive Plants in the Jackson Area
Purple Loosestrife (Lythrum salicaria)
In the 1800s purple loosestrife was brought to the U.S. and Canada as an ornamental and medicinal plant; it soon jumped the garden wall and found our native wetlands to be ideal habitats for its growth and spread. Today, purple loosestrife can be found in every state except Florida. It especially likes wetlands where water levels fluctuate, giving it an advantage over native plants such as broad-leaved cattails. It produces thick stands that contain little else in the way of plants, greatly reducing biodiversity and heavily impacting native wildlife as well as vegetation. In some states it is now illegal to plant this non-native. Fortunately, scientists have discovered an insect from this plant’s homeland that is now being used with some success to keep populations of purple loosestrife under control.
Garlic Mustard (Alliaria petiolata)
First recorded in the U.S. in 1868 on Long Island, NY, this plant was probably brought over by early settlers for food and medicine. Now it has spread as far south as Georgia, north into Canada, and as far west as Kansas and Nebraska. The plants each produce hundreds of seeds, which easily spread and can persist in the soil for at least five years. Garlic mustard often first gets established in disturbed areas (like roadsides), but soon it spreads into the woods, displacing native wildflowers such as spring beauty, wild ginger, bloodroot, Dutchman’s breeches, toothworts, and trilliums. Garlic mustard is also responsible for the decline of at least one, possibly two, native butterflies.
Common Reed (Phragmites australis)
This tall grass, which can easily be confused with our native phragmites, is an aggressive invader of many of our wetlands. Streams, rivers, lakes, ponds, creeks, marshes – all are susceptible to its onslaught. Like many alien plants, common reed grass produces massive quantities of seed and forms homogenous stands that prevent the growth of other vegetation.
Spotted Knapweed (Centaurea biebersteinii)
To the untrained eye, spotted knapweed may look a lot like Canada thistle, which stands to reason since both are in the aster family. This alien came to our country accidentally, mixed in with alfalfa and possibly hitching a ride in the soil that is sometimes used as ballast in ships. Spotted knapweed is found today in nearly every field and “waste area,” where it readily forms a monoculture, preventing the growth of most other plants. Like purple loosestrife, several insect species are now being used to try and get this invader under control.
Canada Thistle (Cirsium arvense)
A member of the aster family, Canadian Thistle has been in the US now for nearly 400 years. Forty-three of our fifty states now designate it as a noxious weed. Its presence in a variety of habitats shows how flexible it is in its needs, and also points to just how invasive it can be. Where this thistle becomes established, it pushes out native plants and completely changes the structure of the biotic community. Its seeds can remain viable in the soil for at least 20 years, making it difficult to eradicate.
Bush Honeysuckles, exotic (Lonicera spp.)
There are seven species of non-native bush honeysuckles that are taking over our landscape: Amur, Bell’s, Dwarf, Fragrant, Morrow’s, Standish’s and Tartarian. All are originally Asian or Eurasian species, and each was brought over to the US as either an ornamental, to provide cover and food for wildlife, or to help control soil erosion; sometimes they served multiple purposes. In the end, however, they out-competed our native plants for light, for soil moisture and nutrients, and even for pollinators. While many people today insist on planting these shrubs for their lovely flowers and sweet scent, the belief that they are also providing important food for birds is misplaced. The fruits of these non-native shrubs are high in carbohydrates, and migratory birds that gorge on them end up not having enough body fat to get them through their long migration flights. Our native birds evolved with our native plants – if you want to help birds on migration, remove the alien honeysuckles and replace them with native shrubs like arrowwood, bayberry, spicebush, or chokeberry.
Autumn Olive (Elaeagnus umbellata)
In 1830, autumn olive was introduced to the US as an ornamental, a wildlife planting, a natural hedge or windbreak, and as a panacea to restore lands that had been overcut or overgrazed. Soon it was off and running on its own. It does very well in poor soils because, like beans and peas, its roots are capable of nitrogen fixation, giving it an advantage over plants that need soils of better quality. Today, rather than seen as the savior of devastated areas, autumn olive is known to out-compete and displace native plants by creating dense shade and interfering with natural plant succession and nutrient cycling.
Multiflora Rose (Rosa multiflora)
Roses have captured the hearts of gardeners worldwide for hundreds of years. The Victorian Age was no exception and in 1866 rootstock of multiflora rose made its way into the US. In the 1930s the US Soil Conservation Service touted this thorny shrub as The Answer for creating living fences on range land, and soon state conservation organizations were promoting it as cover and food for wildlife. Before long, highways were using it for crash barriers along highways and to block the lights of on-coming traffic. Today it is listed as a noxious weed in several states, and in some it is even illegal to plant.
Winged Burning Bush (Euonymus alata)
As the gardening movement was getting going, many plants from overseas were sought as ornamentals in American gardens. In 1860, burning bush was added to the collections of many Americans, primarily for its stunning autumn color and the funky “wings” that grow on the branches. It was colorful and “different,” the perfect exotic. Unfortunately, it was also the perfect invader, for today burning bushes that grow to nearly tree-size are making their way into our forests, along bikeways, into prairies and well beyond the homestead garden. It forms dense thickets, preventing the growth of native vegetation.
Japanese Barberry (Berberis thunbergii)
The darling of parking lots and people who are plagued with deer, Japanese barberry found a willing audience here in the US. Seeds were first sent to the US in 1875 from Russia, and eventually it was the plant of choice for early settlers, who used it to create hedgerows, dyes, and even jams. The fact that its thorny visage is a deterrent to deer only became appreciated in recent years as the white-tail deer population exploded in the wake of aggressive predator control programs and human development. Today you can find this alien forming dense understories in many of our forested lands.
Norway Maple (Acer platanoides)
While several maples are native to North America, this one is not. Introduced as an ornamental, and prized for its dense, dark foliage, which creates heavy summer shade, the Norway maple soon proved to be problematic. The same shade that made for welcome relief from the summer heat also keeps sunlight from reaching the ground and stimulating the growth of other plants. This tree is now a known invader of forests, fields and other natural habitats.
Tree-of-Heaven (Alianthus altissima)
This sumac look-alike first came to North American in 1748 when a gardener introduced it to his garden. A hundred years later it headed westward to California with the rest of the eager seekers of gold. Today it is found across most of the United States. In urban areas it is problematic because its roots seek out (and damage) sewers and other structures. Outside the cities, however, its damage to the landscape is legendary, as it takes over cultivated fields and natural habitats alike. A prolific seed producer, it grows vigorously and soon forms dense stands that preclude all other vegetation.
White Mulberry (Morus alba)
Back when Europeans were first settling in North America, some enterprising individuals decided to try their hands at growing silkworms. Knowing that these caterpillars feed on the leaves of white mulberry, they imported the trees from Asia. The silkworm industry didn’t survive, but the trees did. Today the only states where white mulberry has not spread are Arizona and Nevada. North America has a native mulberry (red mulberry), which once grew quite readily here in Michigan, but soon it was not only pushed aside by the white, but the two also hybridized.
Asian/Oriental Bittersweet (Celastrus orbiculatus)
Once upon a time, American bittersweet was sought as a popular autumnal decoration for homes, but in the 1860s oriental bittersweet came over as part of the trade in ornamental plants. Like so many Asian plants, this vine soon jumped the garden fence and took off into the woods. Not only did it get a foothold in forests and along the edges of fields, where its twining nature left it strangling native vegetation, but it found our native bittersweet and soon they hybridized. Today it is an uncommon joy to find our native bittersweet in the landscape.