Friday, July 3, 2009

Info on Invasive Plants and how to Control Them

A lot of new homeowners in the older suburbs of DC face a big problem. The yards have often been neglected for years, and invasive exotic plants have been allowed to take over.

One client of mine bought her house from its original owner, a WWII veteran and his wife. The couple had lived in their house since the 1950s, and lovingly tended it until finally they could not physically maintain it. What had once been a lovely garden full of azaleas, oak trees and impatiens quickly became a lot overrun with Japanese honeysuckle, mile-a-minute vines and multiflora rosebushes. When the older couple finally decided to downsize to an apartment, the yard was nothing but a viney jungle. My friend loved the house, but found the yard exasperating. Each time she tried to work on the vines, she found she could not tell the poison ivy from the mile a minute, and retreated into the house with frustration.

Another client and friend bought what formally been student housing. College students had rented out the little bungalow near the Metro for years, and the landlord's subsquent neglect of the yard during those decades had left nothing but honeysuckle, English ivy and tree of heaven. Although my friend dreamt of hosting wonderful barbeques and planting oak trees which would eventually shade his backyard, he felt overwhelmed by the vines and the seemingly insurmontable amount of foliage that needed to be removed before he could begin. "You can't even see out of the basement windows on most sides of the house," he said one afternoon. "I didn't even know those windows where there when we bought the place, because the vines covered everything."

For many new, young homeowners or people who have never had occasion to garden before, the problem is so daunting that they don't even know where to begin. They can't even identify the problem plants, and don't know how to control them. What's worse, some of their attempts at removal only make the invading plants grow stronger and more vigorous. Some plants respond well to surface removal. Others might need to be removed root and all. To those who can't tell the ivy from the porcelain berry, the situation can seem hopeless. As a result, the invaders continue to grow abated, going well beyond the boundaries of these yards and into parks and other public green spaces.

There are several great websites out there, however, which can help the average person tackle this problem effectively. I knew of a few myself, but a recent query of mine to the Chesapeake Conservation Landscaping Council netted a host of even more resources. I've listed them below.

A List of Invasive Exotic Plant Fact Sheets and Info on how to Control Them Effectively

Invasive Plants of the Northeast: IPANE

These fact sheets are designed to distribute information about specific invasive plants that exist in the Northeastern United States.

The Global Invasive Species Team: GIST

A somewhat technical guide to controlling weeds.

Invasive Exotic Plants in PA List

From the Pennsylvania Department of Natural Resources, an easy to use list of the plants, their fact sheets, and methods of control. Most of these can also be found in Maryland, and most of the control methods would apply here, too.

**Plant Conservation Alliance’s Working Plant Group

This site has nationwide invasive plants list and excellent fact sheets, too. This one is set up like a round of Wanted posters from the Wild West, with the plants as the criminals. The photos are excellent, and the writing is great for non scientists. Easy to understand, and actually kind of fun to read. Good, easy to understand directions for controlling the plants, in spite of the rather technical sounding title of the site.

Invasive Alien Plant Species of Virginia

This is an advisory list published by the Virginia Department of Conservation & Recreation (VDCR) to inform land managers of potential risks associated with certain plant species known to exhibit invasive behavior in some situations. The species are ranked as highly invasive, moderately invasive or occasionally invasive.

US Forest Service Invasive Species Program

An online portal to Forest Service invasive species information and related management and research activities across the agency and with our many partners. This one goes beyond plants and includes insects and animal pests as well.

**Virginia Department of Forestry

Although some of the info here can be found in other VA websites, this site includes information that is forest specific. The control page is listed at: and is really good for those who might only know the common name of a plant. The control info and the identification info are on the same fact sheets, which makes it quick and easy for homeowners. As with the PA pages, most of these same plants occur in MD, too.

Nonnative Invasive Plants of Southern Forests:
A Field guide for Identification and Control

This entire book is free online, but you need a broadband connection to be able to download this rather sizable document. That said, the photos are excellent. The text is somewhat technical, but most homeowners should be able to navigate through it with relative ease. Control information is also here, but listed separately from the identification pages.

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