Friday, September 11, 2009
Banta-Davis Land plays host to unlikely plants - an invasive garden
Plant enemies have cropped up in a garden on the Banta-Davis Land and what’s worse, they are invited to stay. Carlisle’s new “Invasive Plants” garden features an even dozen of the some of the worst non-native invasive plant offenders in Carlisle. Arborists John Bakewell and Kevin Brown created the garden by collecting the plants from the surrounding woods to give Carlisle residents a hands-on look at what to avoid or what to remove if found anywhere in Carlisle.
Some of these plants are lovely and unfortunately still sold illegally by landscaping companies. Included in the garden are: Japanese Barberry, Asian Shrub Honeysuckle, Buckthorn, Oriental Bittersweet, Norway maple, Euonymus alatus (Burning Bush), Multiflora Rose, Autumn Olive, Garlic Mustard, and Poison Ivy, a native but noxious plant. Each plant is labeled with common and botanical names as well as a brief description of its growth habits and negative impact on Carlisle’s biodiversity.
Non-native versus invasive plants
A native plant is one that originated in New England. Non-native plants in general are not automatically classified as noxious or invasive. Many of the bulbs we plant in the fall are non-native, such as narcissus or daffodils, which hail from Europe. Daffodils are not classified as invasive, meaning they stay relatively where we plant them and have minimal effect on our native environment. Invasive, noxious plants, on the other hand, “escape” from sources such as landscaping, boats, aquariums, cemeteries, imported potted plants or research facilities and run amuck, taking over habitats.
Innocent-seeming foreign plants, such as purple loosestrife, can wreak havoc when they don’t have natural enemies. In Carlisle, they spread into uncultivated woodland and wetland areas where they grow rapidly, reproduce quickly, and take over their environment, becoming the dominate species. Some, such as the Norway maple, are toxic aggressors. “They will kill off everything else in there,” said Brown. Their shallow roots take up all available moisture and release chemicals to kill off competitors growing nearby. Since these plants are non-native, Carlisle’s wildlife has not adapted to eating them, so there are no natural limitations to their growth and no nutritional value to their seeds or fruits.
A good source of information is the New England Wildflower Society’s website, where they have a photo gallery of invasive plants: www.newenglandwild.org/protect/invasive-plants/photo-gallery.
Carlisle boards involved in the planning
Bakewell, a Carlisle resident, was a mechanical engineer before he switched careers and became an arborist. He says his “rant is protection of woodlands” and enjoys focusing on the understory and woodland edge plants. To gain approval and support for the invasive plant garden he met with the Board of Selectmen, Carlisle Conservation Commission, the Carlisle School Committee and the Carlisle Garden Club, which listed the garden as a stop on their Garden Tour.
“I also presented the idea to Gary Davis, Superintendent of Public Works, who was very supportive and told me it would be okay to use an adjacent Green Cemetery water spigot for irrigation,” Bakewell explained. “Gary confirmed that he has no current plans for using the site and that if plans changed the raised beds are easily removed.” The School Committee was interested in using the garden for learning opportunities, he added, since it is within walking distance from the school.
Bakewell asked Peter Alden, a naturalist based in Concord, to help with the large plant labels which include photos and details about the plants.
Natural woodlands progression
In a walk around Banta-Davis, Bakewell pointed out the natural progression from small plants and shrubs to woodlands. “When I look at forest progression,” he explained, “I look for biodiversity.” Ferns and small shrubs should give way to taller plants such as high bush blueberry and bayberry, then smaller to larger trees such as pines, maples, and oaks. But walking down a path parallel to the Green Cemetery reveals row after row of buckthorn and burning bush, with Norway Maple crowding the taller plants, and ornamental bittersweet tangled in the branches. It’s an invasive plant nightmare.
Where did these plants come from? “Some of these plants may have crossed over from the cemetery,” Bakewell explained. He seemed almost sickened by the loss of diversity as he walked the path. Removing invasive plants is difficult, Bakewell said. There is a lot of talk about herbicides or other methods, “but what about some time to just rip them out?” he asked. He pointed out that there’s now a lot of information available about invasion plants, “but the action end is pathetic.”
What to plant
Some action is being taken by the state. Massachusetts maintains a list of plants (www.mass.gov/agr/farmproducts/prohibitedplantlist) that are prohibited to be sold or purchased. Gardeners are urged to check it before letting their landscaper install a plant such as Euonymus alatus (Burning Bush). Unfortunately, landscapers who already had the plants in stock when the law went into effect in 2006 had up to January 1, 2009 to sell prohibited plants.
The Connecticut Agricultural Experiment Station is a good source of information on substituting landscaping plants and offers a booklet called “Alternatives for Invasive Ornamental Plant Species.” It highlights both invasive species and possible replacements. (www.ct.gov/caes/lib/caes/documents/special_features/NativeAlternatives.pdf)
Next project a walking path?
Bakewell and Brown hope to create a labeled walking path to highlight both the native species, such as winterberry and hickory, and the invasive plants that are threatening the biodiversity. “Many townspeople remain skeptical about the destructiveness of invasive plants in our area,” he said. “I think a driving or bicycle tour around Carlisle highlighting an infestation or two of each species would be very persuasive and would probably increase the effectiveness of the identification gallery considerably.” ∆
© 2009 The Carlisle Mosquito