Be on the alert — killer aliens are invading! There is no need to look to the sky for unidentified craft — they won’t be using spaceships. As in a scary Hollywood movie, their spores travel on the wind, or arrive by animal or bird dropping; perhaps even by human hand or foot. These killer aliens are invasive non-native vines which, left unchecked, will kill our trees.
The non-profit group, Plant NOVA Natives, wants you to spot alien vine species in your yard and your neighborhood, to be alert and put others on the alert, to the damage non-native vines inflict.
Plant NOVA Natives’ effort is part of their Tree Rescuer and Plant NOVA Trees campaigns.
In Fall 2021, Plant NOVA Natives launched their focus on planting native trees to increase the native tree canopy in Northern Virginia. The goal: to plant 600,000 trees by 2025. Native trees are known to provide a myriad of benefits to the ecosystem, including as host plants for early stages of pollinators, and are important to reducing climate change by capturing carbon, cleaning air and clearing pollutants from stormwater. This is especially important here in the Chesapeake Bay watershed. Virginia is one of five states in the Chesapeake Bay watershed, tasked by the federal government with taking actions to offset damage to the Bay created by polluted runoff from roofs, roads, and lawns, causing damage downstream.
Despite tree planting efforts, the tree campaign reports, “Northern Virginia is gradually losing tree canopy. Multiple factors contribute to tree death. Some are hard to change on a local level, such as the stress on trees from climate change. Others are within human control, such as poor planting and mulching practices or the sacrifice of trees for more roads, buildings, and park amenities.” Consider the number of trees coming down along the Beltway for expanding express lanes.
One year after the tree planting campaign launch, residents self-reported 7,850 trees and shrubs planted, on the group’s website. During the same timeframe, Tree Rescuers sampling survey of about 4,000 residential acres found an average of one mature tree at risk per acre. The number of at-risk trees on commercial acreage was higher; 6.5 per acre on about 6,000 acres surveyed. That’s over 40,000 mature trees at risk, just in the surveyed areas of the county.
It soon becomes obvious that planting small tree seedlings, even in large numbers, cannot make up for losing thousands or millions of large, mature trees. Saving one mature native tree provides huge environmental benefits.
Yet millions of large trees are at risk of being smothered to death. Vines typically attack trees in the sun along wood edges, but may also be present in open gardens, or almost anywhere. Vines leaves block air and light from the tree bark and canopy, and the vine's roots compete with the tree for nutrients in the soil beneath. When vines get big and spread, they suffocate the tree. Often trees are unable to recover during vine dormancy.
The amount of time it takes to do serious damage depends on the tree and the type of vine. One of the fastest growing vines, Kudzu grows out of control quickly. It is able to spread through runners, rhizomes, and by vines that root at the nodes to form new plants. Once established, kudzu can grow at a rate of one foot per day with mature vines as long as 100 feet, according to Virginia’s Department of Conservation and Recreation (DCR). Nicknamed the “plant that ate the South,” Kudzu can form a continuous blanket of foliage which chokes out competing native trees and vegetation.
Another vine, Mile-a-minute weed is a fast-growing, barbed vine native to Asia. It gets its name from its ability to grow up to 6 inches per day, or 25 feet in six to eight weeks. It also forms large mats of plant material that choke out native plants, leaving no space for tree seedlings to sprout. Other prolific invasive vines in our area include: English Ivy, Japanese Honeysuckle, Oriental Bittersweet, Porcelainberry and Asian Wisteria.
Invasive vines are a problem on all types of land, not only on private lawns and public parks, but also on commercial properties, home owner association (HOA) common areas, the grounds of houses of worship, military bases, Virginia Department of Transportation easements, and railroad and other rights of way.
To some, eliminating invasive vines and other invasive plants seems an impossible task, hard to change on the local level given the size of the problem. But Margaret Fisher, Chair, Plant NOVA Natives Community Outreach Committee, says, “I’m not ready to concede that it’s impossible.” She does know that it will take a concerted effort; one that will need to involve action beyond what volunteer groups do now in area parks.
Fisher sets a scene that would chill a Hollywood sci-fi script writer. She warns, “The problem is growing every year, with nothing so far to stop it. The work that is being done is on such a tiny scale compared to the need, that one can easily predict that by the end of the century, if not sooner, Fairfax County’s remnant natural areas will be almost entirely destroyed. When the trees fall, it is game over, since once the light gets in, the invasive shrubs and perennials explode.”
According to the Arbor Day Foundation, in one year a mature tree will absorb more than 48 pounds of carbon dioxide from the atmosphere and release oxygen in exchange. This makes trees a very important part of our climate change response. When a tree dies, the carbon it had captured is released back into the environment. The Environmental Protection Agency says, “the buildup of carbon dioxide (CO2) and other greenhouse gases like methane (CH4), nitrous oxide (N2O), and hydrofluorocarbons (HFCs) is causing the Earth's atmosphere to warm, resulting in changes to the climate we are already seeing today.”
What Can Be Done on a Large Scale Locally?
The first part of the locally focused effort has been to help northern Virginians recognize the vines and their danger. Tree Rescuer volunteers look for vines in communities and leave informational door hangers. Their work adds to volunteer groups who have worked in conjunction with the county’s Invasive Management Area (IMA) group to attack invasive vines and other plants in area parks.
Recently, Fisher has begun asking for county supervisors’ help, to use the county’s many communication vehicles to include more tree saving information, as a service to residents, adding to the Tree Rescuers and park volunteer effort. In addition, her group advocates for county leadership in including tree saving efforts when contracting for its own landscaping services, and creation of public-private partnerships with businesses, both for trees on their properties and by adopting nearby parks. Plant NOVA Natives encourages engaging the many landscaping and lawn service companies operating in the county to learn about invasive vines and do more to eliminate them. For example, instead of mowing only to a customer’s wood-line or property edge, or to a tree’s mulch ring, contractors could cut invasive vines. Their regular visits for service would be useful in weakening the vines without need for use of chemical treatment. Even clipping back a vine once per season, even if it doesn’t kill it, saves the attacked tree for a period, perhaps years, until the vine regrows to tree-lethal level.
Fisher reports that county supervisors to whom she’s talked so far have been receptive.
The Board of Supervisors environmental committee chair, Dan Storck, expressed interest in “reviewing county efforts to address invasive plants broadly and to move actions forward to create more awareness." While Storck acknowledges he wants to speak with board members and other groups in the community, he has a long standing interest in environmental improvements and draws some parallels with work he and other board members have accomplished recently with the running bamboo problem. His Environmental Committee meets in July and again in October.
What Can Be Done Now by Residents?
Homeowners with invasive vines are urged to tackle them early each season for easiest control. Two types of attack plans may be used: mechanical and chemical. Mechanical means include pulling up by the roots, either by hand or using tools like weed wrenches or root jacks; by suffocating, using double or triple layers of plastic to deny the plants nutrients from the sun; or cutting or mowing. Cutting thick mature vines may include cutting the vines as close to the ground as possible to deprive them of nutrients. For English Ivy, adding a ‘window pane’ cut of six to twelve inches around the tree also cuts off nutrients to the vine, risking less damage to the tree bark than pulling the vines off the tree.
Chemical applications may involve foliar application or cut stem treatments for woody stemmed vines. The Virginia Department of Forestry recommends using only state certified chemical spraying professionals. Homeowners can spur interest in this kind of work by asking their landscape and mowing service providers about this kind of service.
For help in identifying invasive vines, or to volunteer as a Tree Rescuer, see https://www.plantnovatrees.org/tree-rescuers-volunteer-program.
Plant NOVA Natives/Plant NOVA Trees is a partnership made up of representatives from state and local agencies, not-for-profit and for-profit organizations, and numerous concerned residents, pooling their resources to work toward this common goal.