Numerous Suffolk residents gathered Tuesday night to find out more about an invasion that’s costing the United States more than $100 billion dollars annually. These invaders threaten the lush landscapes of Virginia and in many cases were introduced by Virginians themselves.

Residents, city councilmen and many others converged to discuss the topic of the latest Nansemond River Preservation Alliance River Talk: “Invasive Plants: Like watching an explosion in slow motion.”

“It’s a serious ecological problem,” said invasive species specialist Steven Kirkpatrick, who conducted the presentation with horticulturalist Byron Carmean. “By and large, they’re in the rapid growth phase of infestation, and the costs are growing at a very rapid rate.”

About 90 species of plants, amounting to about 3 percent of Virginia’s flora, are considered invasive. These are non-native plants that have been imported into Virginia and have flourished out of control.

They proliferate because they have few natural predators, have seeds that are dispersed far and wide with long viability and many have allelopathic properties that chemically inhibit other plants in their vicinity.

“It will prevent other plants from growing nearby or just kill the plants near it,” Kirkpatrick said.

The Nature Conservancy states that invasive plants have directly contributed to the decline of 42 percent of threatened and endangered plant species in the United States, and the economy loses an estimated $120 million annually because of these infestations. These invasive plants cover 100 million acres across the country, an area roughly the size of California.

“No type of habitat or region of the globe is immune from the threat of invasive species,” according to Nature.org.

Birds are identified as one of the biggest culprits for these infestations. They enjoy the seeds from these plants and either drop them from their beaks or defecate them in another location.

“It’s like packing the seed in fertilizer,” Kirkpatrick said about the bird droppings.

But throughout the country, homeowners have enjoyed having the beauty of invasive plants on their own property. The invasive burning bush is a dense shrub native to Asia that pops with bright colors in the fall.

“They plant these on the interstate,” Carmean said. “They’re beautiful, I’ll admit that, but they’re also growing in the woods because the birds carry their seeds.”

Most of these nuisances are fast growers. Alligator weed, for instance, is relatively new to Hampton Roads but can already be found in many drainage ditches in Chesapeake and Virginia Beach, according to Kirkpatrick.

“It’s taking over my driveway in Chuckatuck,” he said.

Tree of Heaven hails from China and was brought over to the United States as a decorative garden plant. It’s now a problem in 41 states, spreading aggressively by both seed and root sprouts that rapidly grow back after being cut.

“I often suggested that it should have been called the Tree of Hell,” Carmean said. “It’s a horrible tree that grows really fast.”

Another offender growing rapidly throughout Hampton Roads is Japanese stiltgrass. This import grows well in minimal lighting, and each plant can produce up to 1,000 seeds, each one viable for up to five years.

“It’s a real problem, and it’s getting worse,” Kirkpatrick said.

Residents have several options for removing these pesky plants. There’s the old-fashioned mechanical methods of pulling, mowing and cutting. Kirkpatrick recommended combining this elbow grease with herbicides. There are also insects that can halt infestations, like flea beetles and borer moths hungry for alligator weed, but those are much trickier.

“Introducing biologics is a very tricky business,” Kirkpatrick said. “Just ask anyone from Australia about that cane toad business.”

Regardless of the eradication method, Kirkpatrick and Carmean recommended introducing native plants into the soil to immediately begin rehabilitating the ground for a healthier, lusher future.

Visit dcr.virginia.gov for details on native plants and other information.