Greater Harrisburg's Community Magazine

Unwelcome In Our Woods: Invasive species upset the balance of nature, from Pennsylvania’s forests to home gardens.

“Public enemy number one” is how Shannon Powers refers to the spotted lanternfly.

Powers, press secretary for Pennsylvania’s Department of Agriculture, said the invading insect is an $18 billion threat to the state’s economy—specifically products and jobs related to the grape, apple, hops and hardwood industries.

And April is when the spotted lanternfly hatches.

“The biggest thing to remember is invasive species don’t belong here, and they cause problems for the things that do belong here,” said Powers.

She encourages residents to be vigilant. And Powers doesn’t mince words—when spotted, spotted lanternflies should be squashed.

When they first emerge from their gray, mud-like egg masses in the spring, the pests are black with white spots. Through spring and summer, they develop red patches and wings.

The insect, native to Asia, found its way into Pennsylvania in 2014 and has prompted a quarantine across more than two dozen counties, including Dauphin.

This winged invader lives on a plant—with an unlikely name—that is also an invasive species.

“Tree of heaven, host plant for the spotted lanternfly, grows along highways and has big clusters of seeds that are aerodynamically shaped to travel with wind—so you see how easily it can be dispersed,” said Mary Ann Furedi, an ecologist based in Harrisburg. “It has the potential for an economic nightmare for our state.”


Ripple Effect

Furedi monitors invasive plants for the Western Pennsylvania Conservancy in partnership with four state agencies, including the Department of Conservation and Natural Resources.

“An invasive species is basically a non-native species that can cause great harm to the environment, the economy or human health,” Furedi said, quoting the federal definition set in 1999.

Two invasive insects that have already scarred state forests are the hemlock wooly adelgid and the emerald ash borer.

“When you’re driving throughout the state seeing lots of standing dead [ash] trees, that’s the wave of the emerald ash borer,” Furedi said.

Meantime, the fact that the eastern hemlock is our state tree means nothing to the hemlock wooly adelgid. And damage to the state’s most common evergreen has a ripple effect on waterways. That’s because hemlocks literally throw shade—keeping river and stream temperatures cool.

Numerous invasive plants have put down roots along the banks of the Susquehanna.

“Purple loosestrife is showy, with bright magenta rods of flowers, but it’s taken over the riparian zone,” Furedi said. “And Japanese knotweed has formed monoclonal stands, where you’d naturally have different herbs, goldenrod, grasses and seasonal plants.”

In Harrisburg, the city manages Japanese knotweed as best as it can by mowing along the riverbanks to stunt growth, Furedi said. Trimming keeps it from flowering and spreading further.

Why are riverbanks so valuable?

“It’s the interface between the river and the upland area—you have a lot of exchanges going on,” Furedi said. “Riverbanks also help spread out the energy of floodwaters, and there’s a lot of nutrient release. Our beautiful Pennsylvania farmland is associated with our large river system because of those deposits.”


Safe Bet

Closer to home, many home gardeners don’t realize they may be harboring—even planting—invasive species. Furedi said Japanese barberry and butterfly bush are two prime examples.

In fact, Japanese barberry, a compact shrub with small red-tinged leaves, can introduce a whole host of additional issues into your yard. Its red berries attract mice, and the mice, in turn, serve as hosts in the life cycle of ticks.

“Tick-borne diseases are on the rise, and the invasive Japanese barberry is one of the many species associated with it,” Furedi said. “If you want to reduce the potential for tick exposure in your backyard, get rid of barberry.”

Some invasive plants are, incredibly, still readily available at garden centers, but experts like Furedi and officials like Powers encourage consumers to educate themselves on native species before exercising their green thumbs. Many garden centers now cultivate and promote native plant collections, which are always a safe bet for your home garden.

Keeping tabs on all the state’s invasive species, whether they’re plants, animals or insects, is the Governor’s Invasive Species Council of Pennsylvania, which meets quarterly.

Weeding out the state’s unwelcome pests and plants is, quite simply, dirty work.

“We still have the hope that, although there are invasive species, there’s also hope that we can educate people about the damage invasive species can do, so they can be more active about controlling them,” Furedi said. “It’s not an easy task.”

 For more information on the spotted lanternfly, see; sightings can be reported at 1-888-4BADFLY. To learn more about the spotted lanternfly’s host plant, tree of heaven, see The Western Pennsylvania Conservancy’s website is, which includes a section on invasive and unwelcome species.

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