Battling Invasives at Glencarlyn Park

Text and Photos by Devin Reese, except as noted.

Arlington Regional Master Naturalists have a vendetta against invasive plants because of the damage these invaders do to ecosystems. Invasive plants outcompete native plants, disrupting age-old relationships with insect pollinators and typically reducing the biodiversity of an area.

Go on an invasives removal field trip with an ARMN volunteer and you’re guaranteed to witness moments of reckoning between human and plant. Those moments, kicked off by exclamations of dismay such as “Oh no, that’s kudzu!” often involve clipping, lopping, grappling, tugging, hurling, bagging, and otherwise taking invasive plants to the mat. 

If you want to join in the excitement of plant wrestling, there’re plenty of regular outings in Northern Virginia. One of those is the invasives removal program at the Long Branch Nature Center’s Glencarlyn Park in Arlington, monthly on Sunday afternoons. Wear long pants and bring your gloves, clippers, and enthusiasm for helping native plants. The site offers extra gloves and tools if you arrive empty-handed.

One of the people you’re bound to interact with is Long Branch Environmental Steward Steve Young, who is a font of information about the native and introduced flora. He’ll lead you through recognizing and removing invasive plants, while sharing plant-related lore. 

Photo of volunteer holding up a garlic mustard plant
Steve Young shows seed heads on garlic mustard (Alliaria petiolata).

You’ll likely remove garlic mustard (Alliaria petiolata), a common invasive that has cropped up all over the NOVA region. Crush its leaves for a whiff of garlic, which explains its introduction from Europe as a food plant. Despite its tastiness to humans, garlic mustard is not palatable to native wildlife. Because it can self-pollinate or cross pollinate, produce lots of seeds, and grow in shade or sun, garlic mustard spreads fast. Steve will show you how to tug it gently, roots and all, out of the ground, and bag it to keep the seeds off the soil. 

Another plant Steve will point you to is the mile-a-minute vine (Persicaria perfoliata) that was introduced from Asia and first got a foothold in the U.S. at a plant nursery in Pennsylvania, from where it spread. Its delicate stems and leaves bely its hazard as an introduced species. Its other common named, “devil’s tear thumb,” comes from miniscule, curved barbs on the stems and triangular leaves. Using its barbs to cling to other vegetation, mile-a-minute vine grows up to six inches a day, spreading laterally and horizontally. Feel the sticky barbs as you extract the vine from its hold on native vegetation.

Photo of a volunteer pulling a vine
Volunteer Erin removes mile-a-minute vines (Persicaria perfoliata).

Expect Steve to show you some introduced plants that are problematic but cannot be eradicated by pulling them. For example, while small areas of Japanese stiltgrass (Microstegium vimineum) may be removed by hand, it can quickly grow into dense stands to create short, vertical groundcover. Creeping Charlie (Glechoma hederacea) makes ivy-like blankets, but pulling it out will be futile, says Steve. When he first started working at Long Branch about 25 years ago, he says he was “totally anti-chemical and didn’t believe in ever using herbicides.” But he soon realized that “if you don’t use herbicides, you’re going to lose your native plants.” Experienced contractors do regular, targeted herbicide treatments to get rid of invasives that cannot be hand managed.

While battling the invasives, you’ll find moments of gratification in coming across elusive native plants. For example, ghost pipes (Monotropa uniflora), which benefit from the ongoing restoration effort, may peek out of leaf litter with their pale white stems and papery flowers. Lacking chlorophyll, they survive as saprophytes, drawing nutrients from tree roots. Keep your eye out for the equally odd-looking Jack-in-the-Pulpit (Arisaema triphyllum) with its hooded flower. Fold back the hood to see its spike of tiny flowers. The plant is poisonous to humans, but some animals feed on its berries.

Steve may point out the native dogbane (Apocynum cannabinum), that grows in clumps like other bunch grasses. While it is attractive to many insects, Steve notes that this milkweed relative earns its name—it is indeed toxic to mammals.

Photo of the Dogbane plant
Dogbane (Apocynum cannabinum).

The taller native bottlebrush grass (Elymus hystrix) has feathery seed heads. Birds enjoy its grainy seeds. Another is poverty oat grass (Danthonia spicata). While deer resistant, poverty oat grass supplies forage for various insects. These are some of the plants that can transform a yard from turfgrass to habitat for native animals. As Steve says, “these grasses will be taller and won’t look like turf grass, but we have to change our thinking about what a yard can be. Many yards have empty spaces that you would not miss.” 

Photo of a tree sapling in a protective cage

At Glencarlyn Park, you may also encounter some native restoration plantings. Redbud saplings (Cercis canadensis) are enclosed in wire cages to protect them from grazing deer as they mature. 

You may be asked to wrestle the climbing porcelain berry (Ampelopsis brevipedunculata) off the cages to make sure the redbuds get enough access to light. Be careful that you’ve got the right plants, though, because porcelain-berry is closely related to the native grapevines (Vitis spp.) that are valuable to nesting birds. 

Steve’s lively conversation is so information-packed that time passes quickly and you may find yourself looking eagerly forward to the next invasives removal opportunity. 

Learn more on Steve Young’s blog: Plant Whacker, http://www.plantwhacker.com. You can also sign up on the ARMN Volunteer webpage for Arlington County for the Long Branch Park Invasive Plant Removal and other park sessions. The Glencarlyn weed removal event is monthly on Sunday afternoons. 

Additional Wildlife Information (All forms of life that are wild, including plants, animals, and microorganism – Natural Resources Service)

Jack-in-the-Pulpit (Arisaema triphyllum):

One of the more distinctive plants on VA forest floors, Jack-in-the-Pulpit is native to all of eastern North America. Each plant produces a large, fleshy flower on its own stalk, adjacent to a separate stalk with several leaves. The way the flowers’ sheath (the “spathe”) encloses and curls over the flower stalk (the “spadix”) explains its common name. The spadix (Jack), however, is actually hermaphroditic, able to produce male flowers, female flowers, or both. A plant growing just male flowers on the spadix has a hole at the base of the sheath that allows pollinators to do their job and then escape through the bottom. The plants growing just female flowers, however, lack the hole; the theory is that insects get trapped and pollinate as they writhe around.

Learn more on the USFS website about Jack in the Pulpit.

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