Hildy Ellis’s nemesis is the Norway maple tree. She’s been tackling the shoots and saplings in her yard, and she thinks she’s gotten ahead of them. But she understands that Norway maple is an invasive species in Maine and as such, will be tough to beat. 

Ellis, a district coordinator for the Knox-Lincoln County Conservation District, was the presenter at the Boothbay Region Land Trust event, Invasive Plants, Walk and Talk, on Friday, June 30, at BRLT’s newest preserve on Oak Point Road in Boothbay Harbor.

According to the Maine Department of Agriculture, Conservation & Forestry, an invasive plant is characterized by three criteria: They are not native to Maine; they have spread or have the potential to spread into forests, fields and natural areas, and they cause harm by developing populations that negatively impact the environment, economy, or human health.    

Ellis explained that invasive plants have developed systems that enable them to circumnavigate systems set up by Maine’s native plants, such as fast-spreading root systems, climate adaptability, growing rate, and chemicals released into the soil that either poison native plants, change the pH of the soil, or prevent anything else from growing near the invasive root system. Sometimes, they charm onlookers, like purple loosestrife, or Rosa rugosa (beach roses), or multiflora roses, which are a lovely white and smell sweet.

One hundred billion dollars is spent annually to control invasive species throughout the U.S., Ellis said.

She brought several examples of invasive plant species, took examples from the audience, and passed them around for a closer view. One of the first plants to make the rounds was Asiatic bittersweet.  “Bittersweet is the north’s kudzu,” Ellis said. Kudzu is a vine system that has overwhelmed and killed native plants throughout the south.

“Bittersweet acts like a boa constrictor, wrapping itself around small trees and strangling them. It also covers tree canopies and keeps out the sun, which eventually kills the host tree,” Ellis said. Bittersweet is often used in holiday wreath-making because the berries are so pretty and the flexible vines are easy to braid and shape into a circle. North Carolina has banned the use of Asiatic Bittersweet in wreaths, because when the wreaths are discarded in a dump or a backyard, seeds in the berries disperse and grow. She advised the audience to burn invasive plants uprooted from the ground or pulled down from trees, because their adaptability to almost any growing situation assures they will thrive if they’re tossed out.

It’s important to note, there is an American bittersweet, which is native and should be allowed to grow, Ellis said.  

Ellis passed around several other examples of invasive species to help with identification, including Japanese knotwood (also known as Mexican bamboo), common buckthorn, burning bush, multiflora (rambler) rose (once used as a fence to keep livestock in), and Japanese barberry which, Ellis said, is overrunning both Monhegan Island and the Rachel Carson Preserve in Wells. The barberry “takes Maine’s acid soils and makes them alkaline,” she said. 

Other plants to learn to identify and eradicate, when possible, include black swallowwort, golden ragwort, hardy kiwi, ornamental jewelweed, loosestrife and yellow iris.    

It’s important to rid property of invasive species. “Start as soon as you see it,” advised Ellis, before it gets out of hand. She said it’s important to develop a management plan before tackling the chore of getting rid of an invasive plant.

First, the plant should be positively identified and researched. If it has already breached the property, care should be taken that no new areas are affected. Develop a strategy. How will the plant be killed? Will herbicides and weed killers used? If so, how much, and in what proportion? What is the proper way to dispose of the plant? Constant monitoring is key. Understand that it may take multiple years to rid property of invasive plants.   

Ellis said that to prevent invasives from pirating the yard in the first place, use or rent clean equipment free of seeds when gardening or working in the yard. Understand which plants are invasive, and which are native. Research whether or not a plant is native before buying it and planting it in the yard.

Beginning Jan. 1, 2018, Maine has prohibited 33 invasive terrestrial plants from being sold, propagated, or imported. For a complete list, go to http://www.maine.gov/dacf/php/horticulture/invasiveplants.shtml.  

For more information, contact Ellis at (207) 586-2040.