Environmentalists name the 'dirty dozen' plant species damaging Long Island

In a wooded ravine in the Sands Point Preserve on Monday, a mini excavator pulled English ivy from the forest floor. Native plants, such as spice bush, hickory and winterberry, were marked with pink plastic ribbons so they would be left alone.

Uprooting a quarter-acre of ivy is the first phase of an ambitious plan to remove invasives from the 216-acre preserve and replant it with natives. The ivy, along with more than a dozen other non-native plant species, has invaded the preserve in North Hempstead and other forests throughout Long Island and along the Eastern Seaboard. 

Environmentalists leading the initiative called the species "the dirty dozen" — among the most pervasive and most common on Long Island. At a news conference, they urged the public's help in eradicating them: porcelain berry, bamboo, phragmites, Japanese knotweed, tree of heaven, Oriental bittersweet, Japanese barberry, multiflora roses, Chinese wisteria, mugwort, burning bush and English ivy.

The plants are tough and can outcompete natives for water, nutrients and sunlight. Invasives also create ecological dead zones: Native animals have not evolved to eat them, so the plants don’t support the rich biodiversity that a native forest would.

“If we don’t have native plants, we don’t have native wildlife,” said Marshall Brown, executive director of the Long Island Conservancy.

At the same time, invasive plants support invasive insect species. The spotted lanternfly, which threatens local wineries and vegetable farms, loves the tree of heaven; both are native to China.

“That’s home cooking to the spotted lanternfly,” Brown said.

According to the U.S. Forest Service, invasive plants have crept in to 133 million acres of federal, state and privately owned land nationwide — an area equivalent to California and New York combined. 

The plants' beauty can be tempting for gardeners. But those who enjoy the porcelain berry’s shiny fruits, burning bush’s bright fall foliage or Chinese wisteria’s purple panicles of spring flowers should consider uprooting them and planting a native species instead, environmentalists said.

English ivy, for example, is prevalent in home gardens and corporate landscaping, but its resilience makes it a pest in natural settings: As it climbs up the trunk of a tree and extends along the branches, it starves the tree of light and nutrients and slowly smothers it. Similarly, bamboo spreads vigorously and thickly, preventing native seedlings from taking root.

Long Islanders may think that a plant like burning bush couldn’t be an ecological hazard if it's in their yard, said Frank Piccininni, co-founder of the Long Island Conservancy and partner in Spadefoot Design, a landscaping business doing the work.

But, “Tell that to the birds who are eating the berries, flying off to beautiful preserves like this, pooping and creating more burning bush everywhere,” Piccininni said. “Getting rid of the bad guys will really help the good guys.”

A $4,000 grant from the Manhasset-based Greentree Foundation is paying to remove the ivy from the preserve. It would cost about $70,000 to remove all invasives from the rest of the property, according to Jeremiah Bosgang, director of the Sands Point Preserve Conservancy. 

And that's only half the battle, said Mark Murray, project manager at Spadefoot Design.

“When you remove invasives, you leave a void,” he said. “If natives aren’t planted there, the invasives will move back in.”

The results of such eradication and replanting efforts can be significant, said Kristen Laird, executive director of the Science Museum of Long Island.

In 2019, the museum began ripping out kudzu that had invaded the museum’s Leeds Pond Preserve. Native shrubs and wildflowers are growing in its place, and the native animal species have returned, she said.

“We have two new fox dens,” Laird said, along with coyotes on the property.

Invasive species have been spreading for decades, and restoring the preserve's native flora is going to take time, environmentalists said.

“This is generational work,” Brown said.