At the peak of the fall season, the trees along the George Washington Memorial Parkway are alive with color. This scenic roadway is one of the most-visited parts of the National Park System, and an autumn drive along this stretch of the Potomac River in the Mid-Atlantic is a joy for tourists and locals alike. Sycamores and tulip trees, dogwoods and maples—these Virginia hardwoods greet visitors with a dazzling display of scarlet and gold.
Now, as fall gives way to winter, the only splashes of color are green. Most of them belong there: Virginia pine, American holly, and an assortment of native ground covers. But as I drove the parkway to NPCA’s Washington, D.C., office this week, I was struck by the proliferation of greenery that the woods could do without: English ivy.
Since its introduction by European colonists in the 18th century, English ivy (Hedera helix) has tangled itself in our culture, from the halls of Princeton to holiday wreaths. And because of its durability and glossy appearance, it remains a popular ornamental, planted as a ground cover by unwitting homeowners.
Unfortunately, English ivy is an invasive species, and an aggressive one at that. It spreads readily by runners or by birds that disperse its seeds, and can quickly form a canopy that crowds out the native species of the forest understory. Even large trees are at risk; along several stretches of the Parkway, entire mature trees are wrapped from trunk to top by the ivy, which deprives them of sunlight and sends them into a steady decline that will eventually kill them—if the weight of the vines doesn’t help to bring them down in a storm first.
Because the parkway is adjacent to residential neighborhoods, it is particularly susceptible to infestation by English ivy, which, along with other invasive species like bush honeysuckle and kudzu, creates an ongoing challenge for the National Park Service staff and volunteers who regularly gather to remove them. But the problem isn’t an isolated one. Present in 18 states and the District of Columbia, English ivy has been reported as invasive in national parks from Shenandoah to Yosemite.
This holiday season, as many of us are making our New Year’s resolutions—and going through seed catalogs planning our spring gardens—you can make a few easy changes that benefit your neighborhood and your parks.
How you can help
- Choose native plants. A variety of ornamental vines and ground covers make better landscape alternatives to ivy, and choosing plants that are adapted to your region can be a great benefit for birds and other wildlife, too.
- Lend a hand. Most parks offer volunteers the opportunity to put on some gloves and help to remove invaders.
- Learn more. Taking a few simple steps when you garden, hike, and boat can help to reduce the spread of invasives and the risk to parks.
About the author
Todd Christopher Senior Director, Digital & Editorial Strategy
Todd guides NPCA's content strategy and leads the team that produces our website and magazine. He is also the author of The Green Hour: A Daily Dose of Nature for Happier, Healthier, Smarter Kids.