Attacking Invasive Species

Pulling weeds is fun.

Really--we’re not making this up. Tearing out non-native, invasive plants is productive, and provides protection for parks, plus the act of ripping out an invader provides an emotional rush. The repetition of pulling weeds, however, brings the realization that this might be a long and--if not done quickly--losing battle.

The Fairfax County Park Authority wins some battles before the enemy establishes its stronghold. The Northern Virginia agency has initiated an Early Detection, Rapid Response (EDRR) program to identify and remove small infestations of invasives before they become serious problems.

Invasive plants rarely are overnight sensations despite fanciful names like “mile-a-minute” that are, thankfully, an exaggeration. There is a time when invasive plants can be removed, not just limited.

Is It Serious Yet?

A serious infestation begins with one or two individual plants that happen to find ideal conditions. Imagine if someone could recognize that original loner as the area’s next kudzu or multiflora rose? Wouldn’t it be easier to remove that one plant than face a tangled hillside or a forest permeated by invasive-plant species?

EDRR is like a treasure-hunter seeking something new, rare or unusual. In Fairfax County, treasure-hunters seek plants that are not native to Virginia. The reward is keeping them out of natural areas.

The program is based on the Early Detection & Distribution Mapping System ( Other valuable sources of information include the work of botanist Les Mehroff and the University of Connecticut’s Invasive Plant Atlas of New England ( and The National Invasive Species Council (

Two-Pronged Attack

EDRR consists of two parts that are separate, but equally important.

Part one asks, “How do you find one plant in the Hundred-Acre Wood?” Early detection is finding an invasive plant that you don’t know is there but you do know that putting off a problem can have awful consequences.

The silver bullet is knowledge--knowing which plants might be a problem. That’s a two-step process. Step one is to become familiar with the habits of the native plants in the region. Step two is developing the ability to recognize something that isn’t part of step one.

This is preparation. In this case, preparation is learning:

• What you have

• What’s out there in nearby habitats

• What could be moving toward your region

• What could become a threat.

In our mid-Atlantic location, buffered by the Chesapeake Bay and an ocean on the east and by mountains on the west, we keep an ear open for reports of plants that are migrating north or south from other Atlantic Coast regions.

In the past year, we have found three new threats. We had an unnerving run-in with the spiny prickly castor-oil tree (Kalopanax septemlobus), which can reach 90 feet and sports thorns about ½-inch long. It had been reported once before in Fairfax County. We’re keeping an eye out for more.

Harmless-looking wavy leaf basket grass (Oplismenus hirtellus ssp. undulatifolius) might look like a nice addition to a forest ecosystem, but native forest floors are supposed to be a kaleidoscope of flowers, grasses and leaf litter--not a monotonous green carpet. This species has spread to hundreds of acres in nearby Maryland and to a few preserves on our side of the Potomac River in Fairfax County. We’ve not spotted any on parkland.

Two reports of marshdew flower, a.k.a. wart-removing herb (Murdannia keisak), caught our attention. This invasive plant is widespread in southern coastal Virginia, but it’s not common in Fairfax. Like other aquatic invasives, control of this East Asia invader is difficult and requires an herbicide. Getting a handle on the distribution of M. keisak is a priority for our program.

We’re also watching Giant Hogweed, which is working its way south from New York and Pennsylvania, and Cogon Grass, which is moving north from Alabama, Georgia and the Carolinas.

Timely Removal

Rapid Response, the second part of EDRR, is about quick and efficient plant removal followed by monitoring. When an unfamiliar or new plant is found, land managers and volunteer botanists determine if it is a troublemaker. Finding these small populations is an efficient use of available resources, and eradication is easier when dealing with only a few plants.

There are precautions to take before plants are pulled.

“We have cultural resources and resource protection areas to consider,” says Invasive Management Area (IMA) Volunteer Coordinator Kathy Frederick. “We just can’t go out and remove plants.”

It is critical to record sightings and follow up. Park personnel need to know exactly where that plant is located in order to determine how it arrived, and to establish regular perusal of the area for any fellow invaders. “We GPS the location so that we can go back to make sure there were no seeds in the soil,” Frederick says. Volunteer botanists monitor areas in subsequent years, and Frederick adds that thanks to their data, “We can see the progress being made.”

This two-part EDRR system is part of a bigger picture. The county park authority has a successful and community-based IMA volunteer program that aims to create hotspots of local biodiversity in neighborhood parks. The five-year-old program has attracted over 3,600 volunteers who have donated more than 15,000 hours to remove invasive plants from about 45 acres at 51 park sites. The program gives residents an opportunity to protect their park plants and wildlife while spending time outdoors, meeting people and restoring natural habitats.

EDRR is the next logical progression in the IMA program, and it will help protect parks from the next wave of non-native invaders.

Going Native

In about half of the IMA plots, we are returning native plants to areas that were infested by invasives. IMA volunteer leaders Robert and Teresa Cortesi reported from one area that their group’s bird expert said, “There has been a lot of noted bird activity on the ground that we have cleared. That is good news.” Volunteer leader Bryant Bullock, working at a different site, echoed, “I found a native in the park I have not seen before.”

The agency seeks naturalist volunteers for the EDRR program. These naturalists undergo an orientation to learn how to:

• Lead, organize, and manage a group of other volunteers

• Conduct systematic surveys of designated parkland

• Identify targeted plant species

• Record their location via hand-held GPS units

• Log data into an established website.


The park authority depends on these volunteer treasure-hunters to look for invasive plants in parks. The IMA program also helps create partnerships. “We worked with two Girl Scout troops that operated like locusts clearing the parkland,” says volunteer leader Stacy Evers. “The girls were focused and took a lot of pride in filling the bags.”

We ask volunteers heading to the parks to take along a digital camera, shoot pictures of anything suspect, and send the shots to us. That’s the best way to make sure we know what is in the parks.

The EDRR volunteer teams can assemble and quickly manage any of these new species that aren’t supposed to be in our natural areas.

The larger goals of maintaining our natural areas and restoring the integrity of our native ecology depend on EDRR.

David Ochs is the Stewardship Communications Manager for the Resource Management Division of the Fairfax County Park Authority. He can be reached via e-mail at

Meghan Fellows is a Natural Resource Specialist and Invasive Management Coordinator for the Fairfax County Park Authority. She is the Secretary for the Mid-Atlantic Exotic Pest Plant Council. She can be reached via e-mail at