Invasive Exotic Plants on the Appalachian Trail
John Odell ate coltsfoot at dinner when he visited Japan. He describes it as textured like Swiss chard but with a different flavor. But in the United States, coltsfoot is an invasive exotic species that crowds out native plants, takes over a region because it has no natural enemies, and threatens native biodiversity.
Mr. Odell, the resource management coordinator for the Appalachian Trail Conservancy's Southern Region, organizes work parties of volunteers to identify and pull out invasive exotic species from the Appalachian Trail.
The big event, planned for April 23, will really be a party, focusing on removing garlic mustard from Max Patch, one of the signature balds and destination on the A.T. The ultimate goal is to remove the invasive weed garlic mustard (Alliaria petiolata) from the land surrounding the Appalachian Trail.
Garlic mustard was introduced from Europe in the 1800s and has spread prolifically in North American natural areas due to a lack of natural controls and its release of allelopathic chemicals that inhibit seed germination of other species.
ATC and the Southern Appalachian Cooperative Weed Management Partnership host several workshops annually to address the issue of invasive exotic (IE) plants, but The Great Garlic Mustard Gathering, as it is called, will be different.
ATC aims to make this a fun event with teams competing to pull the largest amount of garlic mustard from along the trail, while providing instruction on the threats of IE plants, how to identify them, and what techniques are used to monitor and remove these infestations to protect native biodiversity. After a morning of garlic mustard removal, the group will gather on nearby Max Patch for a potluck picnic.
Raising Awareness Of Invasive Exotic Plants
One of the goals of the picnic is to raise awareness that many invasive exotic plants can be used after they're removed. These non-native invaders wreak havoc on our native ecosystems, but have properties that can be useful to human beings. Garlic mustard, for example, was introduced as a culinary herb from Europe, and the leaves have a mild flavor of garlic and mustard.
Cooks and gourmets are encouraged to find ways to use these plants after they're pulled out. The traditional way to incorporate garlic mustard in your diet is in pesto sauces by substituting the IE for some of the basil. Garlic mustard can be dried, crushed, and used as another ingredient in your spice cabinet. But Mr. Odell challenges volunteers to be creative.
The locations for these IE removal programs with volunteers are carefully chosen to attract volunteers to an inviting, accessible site. At over 4,600 feet, Max Patch is an open, grassy summit with glorious views. A.T. hikers consider Max Patch one of the highlights of their journey and remember it long after the rest of their journey becomes a blur. The U.S. Forest Service currently manages the bald by mowing and controlled burning. Just as important as its beauty, Max Patch is only a quarter-mile walk from its trailhead, making it an easy destination to reach.
Experts on IE talk about a "vector of spreading." Prime areas of infestation can be at a road crossing, on the A.T. itself, or a river. Invasives are less likely to spread deep in the woods.
Invasives In Our Backyards
Most IE plants are attractive and look harmless. My favorite is multiflora rose, planted by settlers as a natural fence row. It grows rapidly and was used to contain livestock. It can be seen on the edges of trails in the Great Smoky Mountains National Park, signifying that there was a homesite here.
This species was introduced into the United States by the horticulture industry from Japan or eastern Asia after World War II, when it was advertised as a "living fence" that would promote the privacy of residential properties. According to Mr. Odell, there's even a myth that it was planted on road mediums because it grows so thickly that it could stop a car going across a medium. The rose is spread by birds so it can be found deep in the woods. The conventional use for multiflora rose is rosehip tea.
But one can only eat so much garlic mustard or drink rosehip tea. What is done with most of these noxious plants after they're pulled out of ground?
"Much depends on the quantity and location of the infestation," Mr. Odell explains. "You can cut the plant down and apply herbicide to the stumps and pile them in one area. You can spray the plant. If you pull them by hand, you bag them, haul them to a landfill, and burn it."
How invasives are handled depends on the size of the plants and location of infestation. You would not want to use herbicide next to water. If it's a large infestation, you just pile up the plants.
Invasives are certainly a problem A.T.-wide and nationwide, but more resources might be applied in the South to fight this problem. The Southern Appalachian Cooperative Weed Management Partnership helps recruit and train volunteers. In the South, most of the A.T. goes through U.S. Forest Service land. That means that except for the 71 miles in Great Smoky Mountains National Park, ATC only has to deal with one owner. Other A.T. areas go through private land, which might become a problem when taking volunteers and especially using herbicide.
ATC uses an inventory protocol, Early Detection and Distribution Mapping System, which allows anyone to report invasives so that these plants can be tracked. Each ATC region uses the same protocol and eventually the whole A.T. will be on this system.
Good Invasives, And Bad Invasives
But if we think about the expression, invasive exotics, there must be local, non exotic invasives. Poison ivy is probably the most familiar nuisance plant. It's an invasive but it's our invasive. Another one is jewelweed. These native plants may take over an area but they don't do as much damage because they coevolved with native insects and other plants.
Conversely, most exotics are not invasives. The annuals that we plant in our gardens, such as marigolds and petunias, usually confine themselves to the area where they're planted. Hybrid roses stay put.
Chinese Silvergrass (Miscanthus sinensis), another IE, has conflicting uses. Chinese silvergrass is a tall, up to 12 feet, densely-bunched grass that invades roadsides, forest edges, and old fields. Gardeners are still planting it in their yard. But while A.T. volunteers are pulling out this problem plant, others are growing it as a potential biofuel.
"I'm very skeptical that it can be used as a biofuel," Mr. Odell says. "Some groups are actively planting it, not just using plants in the wild. They claim to use sterile plants but the plants may revert back to being able to reproduce."
But not all problem plants confine themselves to the A.T. or out in the wild. I've been pulling out honeysuckle from my backyard fence for years, and it keeps blooming. It was brought to the U.S. from Japan as an ornamental.
Many other IE species, if not edible, have certain properties that can be used to our benefit. Kudzu and Japanese honeysuckle have been used for centuries for their medicinal properties and for weaving baskets.
The wood from the invasive exotic princess tree is prized for its character and workability, and other plants can be used to make paper, ink, dyes, or other crafts. At The Great Garlic Mustard Gathering, all participants are encouraged to bring a “show and tell” item or culinary dish made from an invasive exotic plant in order to create a dialogue for how we can creatively utilize these plants rather than viewing them simply as a problem.
Mr. Odell explains that "we have a desire to use the plant instead of demonizing it.
Want to help?
Mr. Odell encourages volunteers to come out to one of the IE eradication blitz. You can email him at firstname.lastname@example.org.
Here's the schedule:
* April 9 – Lemon Gap garlic mustard/Japanese spiraea removal
* April 23 – The Great Garlic Mustard Gathering, Lemon Gap/Max Patch
* April 30 – Rain Date for The Great Garlic Mustard Gathering
* May 7 – Carvers Gap/Roan Mountain control and inventory of invasive plants
* June 3, 4 – Stecoah Gap control of multiflora rose and Japanese stiltgrass.
* June 26 – Hot Springs kudzu control (contact email@example.com for info)
* August 5, 6 – Sam’s Gap control and monitoring of Chinese silvergrass (Miscanthus sinensis)