Sections Supplements

When Green Is Not the Way to Go

Invasive Plants Can Be a Growing Problem for You or Your Company

John Prenosil

John Prenosil

Green isn’t always good — at least when referring to invasive plants.
Take a look in your yard when you get home. Do you see a burning bush? Japanese barberry? Norway maple? Yes, you guessed it. These are all invasives, as they’re called, which means they shouldn’t be there.
First off, let’s define what constitutes an invasive plant. These are non-native plants that share these characteristics: they begin growing earlier in the spring and grow longer in the fall than native plants, are typically more tolerant of poor soil conditions, grow vigorously, produce large amounts of seeds, grow well in disturbed environments, and have no natural enemies. Understandably, many invasive plants were historically chosen for landscaping because they required little maintenance, grew well in poor soils, and were disease and pest-resistant.
Burning bush was popular for its brilliant fall color, Japanese barberry for its durability and attractive purple and red leaves, and Norway maple for its summer-long crimson red foliage. These invasive landscape plants and more than 100 other plant species are currently identified by the Mass. Department of Agricultural Resources as prohibited for sale.
It is important to control and/or eradicate invasive plants in wetlands and forest environments because they disrupt habitats by outcompeting native plants, thereby decreasing biodiversity.
Try this analogy. A restaurant with two items on the menu is not as appealing to consumers as a restaurant with 50 items on the menu. An environment with only two items on the menu has low biodiversity; numerous items on the menu mean higher biodiversity. Animals like menus with more diversity. An environment comprised of multiple native plant species offers a host of food choices and habitat to a wide variety of wildlife. Fewer food choices results in a decreased mix of wildlife.
Invasive plant seeds are spread through birds, wildlife, and construction equipment. Aquatic invasive plants are inadvertently spread by boaters from plant fragments stuck to the hull or floating in bilge water. Many of the invasive plants found in our waterways, ponds, and lakes are a result of aquarium plants being flushed down the toilet.
Because established populations of invasive plants are difficult, costly, and time-consuming to control, early detection is paramount. Smaller populations are easier to monitor and control. Control of invasive plants requires a thorough knowledge of the target species, its biology, and an understanding of the environment in which invasive plants are found. Each situation is unique and requires a custom approach. Although herbicides are important for control of invasive plants, they are not always the best alternative.
Integrated Pest Management (IPM) offers a more comprehensive approach to controlling pests, including invasive plants. In addition to simply spraying invasive plants with herbicides, IPM addresses cultural practices and biological controls. An example of a cultural control would be mowing a section of road right-of-way (adjacent to a pond) instead of applying herbicide, which has the possibility of contaminating the water; mowing provides a non-chemical control method to keep the invasive plant population under control. An example of a biological control would be releasing an insect that has been found to eat a specific invasive plant. The goal of IPM is to use the least amount of herbicide to control a population of invasive plants. Eradication is not always necessary. Further, continual use of herbicides on the same plants may result in those plants developing immunity to the herbicide.
Control and eradication of invasive plants typically requires permitting through local and state agencies and application of any pesticides on property other than one’s own requires licensing and certification through the Mass. Department of Agricultural Resources. Licensed and certified professionals should ensure that people are not exposed, groundwater and surface waters are not polluted, wildlife is not be harmed, and damage to non-target plants is minimized.
Resources are available for landowners wishing to improve wildlife habitat on their property. The U.S. Department of Agriculture Natural Resources Conservation Service offers the Wildlife Habitat Incentive Program (WHIP), a voluntary approach to improve wildlife habitat that includes cost sharing up to 75% and technical assistance. Additional online resources related to invasive plants are available through the New England Wildflower Society (www.newfs.org/
protect/invasive-plants) and numerous other organizations.
The reader should keep in mind that this article is meant only for informational purposes. The author does not recommend that the reader apply herbicides or utilize other forms of control on their properties without first consulting an expert. Permits may be required.

John Prenosil is president of JMP Environmental Consulting Inc., which has completed WHIP-funded and other invasive-plant eradication and control projects throughout Massachusetts. Related services also include initial habitat assessments, invasive species management plans, eradication and control, and long-term monitoring; (413) 272-0111; [email protected].