Growing Local: Arlington’s Native Plant Nursery

Recommendation #11 of Arlington County’s Natural Resource Management Plan is to “promote the use of native plant species in County-sponsored plantings and enhance the ability to procure local ecotype plant stock.” In order to address this recommendation, the Parks and Natural Resource Division established a new native plant nursery.  The nursery is located at 4200 S. Four Mile Run Drive, behind the George Washington University baseball diamond.  Construction on the nursery began in fall of 2014, with help of several Arlington Regional Master Naturalist volunteers. In addition to the nursery, there is also a greenhouse that can be used for propagation during winter months.

Why local?

According to DPR’s 2013 Planting Policy, the use of regionally propagated plant material and local ecotype plant stock provide the greatest opportunity for long-term plant survival, provide the highest ecological value, and are genetically matched to the local growing environment. To be considered “locally native,” plant stock must originate from a location less than 150 miles from Arlington. In general, Arlington County uses locally native plants for restoration and recovery of natural lands. Unfortunately, local ecotype native species, propagated from locally collected seed, have very limited commercial availability.

Planning, design, and construction

The first step in the development of the new nursery was to learn from other native plant nurseries in our area, including Earth Sangha Native Plant Nursery and Pope Farm Nursery. Both of these nurseries grow locally native plants for use in restoration activities in Fairfax, Montgomery, and other local counties.  They provided information about construction materials and raised bed design, as well as which species were easiest to propagate.

Seed collection and propagation


Since spring of 2015, Arlington County staff and Arlington Master Naturalist volunteers have been collecting seeds for and propagating several native plants in DPR’s new nursery.  Seeds were collected in Arlington and Fairfax counties, at several park locations. Timing for these expeditions must be just right, so collecting locations must be monitored closely to determine when the seeds are ripe. Once the seeds are collected, they have to be cleaned and stored until the appropriate planting time.

Species planted include herbaceous plants such as common milkweed and creeping bushclover, and shrub species American strawberry bush and possumhaw viburnum.


Plans for the future2

In 2015, we will expand the number of species propagated in the native plant nursery, as well as strengthen our methods for recording data on seed collection locations and propagation methods. Hopefully, we will be able to work with our regional partners to develop a manual on native plant propagation that can be used as a platform to share information and best practices.

We will continue to build partnerships with volunteer groups such as Arlington Regional Master Naturalists, Northern Virginia TreeStewards, and the Master Gardeners of Northern Virginia to manage the day-to-day tasks at the nursery, as well as seed collection and cleaning.  For more information about how to get involved please contact Sarah Archer as




To Cut, or Not to Cut: Exploring Alternative Management Tools for Invasive Plants

What is the best way to manage invasive plants? There are many factors to consider before deciding on a particular management strategy. For instance, you wouldn’t treat a dense infestation of kudzu the same as a few plants of garlic mustard. Beyond the species and infestation level, other factors include site location and accessibility, season, and financial or labor resources available.  Arlington’s Invasive Plant Program started as a mostly volunteer-driven effort.  As the program has grown, we have started incorporating both mechanical and chemical methods for managing invasive plants, but are there others ways? The 2010 version of A Management Guide for Invasive Plants of Southern Forests outlines the four types of management available for invasive plants.

removing invasives

Cultural Methods

Cultural Methods for managing invasive plants include any activities (besides cutting, pulling, or spraying) done by humans to manage invasive plants. One of the most important ways to stop the spread of invasive plants is education. Stopping the spread of invasive plants can be as easy as not planting it in the home landscape.  Another example of cultural control is the use of fire to manage certain invasive species in a prescribed burn.  Also, at certain sites, managers can utilize Water-Level Manipulation, both reducing and increasing water-levels can reduce invasive plants at a particular site, depending on the species.  Mulching and Solarization are other tools for managing invasives by manipulating the plants access to the sun, either by blocking it out or using it to make an environment that is too hot for plants to survive.  Finally, managers can replant areas with native plants to compete with or shade out certain invasive plant species.

Goat eating plants

Biological Methods

Traditional Biological Control Methods include the use of any biological organism such as insects or diseases to limit the impacts of invasive plants. One example is the Mile-a-Minute Weevil.  Another example that has been in the news lately is the use of cattle, goats or sheep in Prescribed Grazing.

mechanical methods

Mechanical Methods

Mechanical methods include both Manual Methods, either hand-cutting or pulling plants as well as Mechanical Methods with heavy equipment.  Volunteers can help a lot with manual methods for removal, but in most cases this leaves the roots of the plants intact and requires additional follow up.  Mechanical methods can be effective but may also cause a lot of disturbance to the surrounding habitat.

Chemical Methods

Finally, chemical tools can also be used to manage invasive plants. In some situations the use of herbicides can be the quickest and most cost-effective way to manage invasive plants.  However there may be impacts to the surrounding habitats.  There are Selective Herbicide Applications, which can minimize damage to desirable plants.  For more infested areas, Broadcast Herbicide Applications may be the appropriate choice.

Photo by Steve Manning,

Photo by Steve Manning,

Management Options for Arlington County

A 2014 Virginia Tech Masters of Natural Resources Capstone Project, called Invasive Plant Management Strategies in Northern Virginia, gave a comparative analysis of invasive plant management practices in the northern Virginia area, including theCity of Alexandria, the City of Fairfax, the City of Falls Church, Arlington County, Fairfax County, Loudoun County, and Prince William County, as well as federal, state, and regional properties. The author, Joan Martinez Allen, interviewed natural resource managers and made observations and recommendations for the region.

She concluded that Arlington County has what she considers an established invasive plant management programs because we have Natural Resource staff, management plans, prioritization strategies, data collection, plant inventories, and volunteer programs.  One recommendation Allen gives, is that Arlington should employ a full use of management tools.  Although in the past we have experimented with several cultural methods, we could explore more opportunities to pilot new management programs.  Allen suggests prescribed burning, the use of biocontrols, and (because of their selective browsing on native plant species) deer culling to help manage invasive plant species in Arlington.

If you would like more information about Joan Martinez Allen’s report, or to participate in invasive plant removal project planning discussions, please contact the Invasive Plant Program at (703) 228-1862.

Pulling Together: Creating a Cooperative Weed Management Area to Manage Invasive Plants

Invasive plant species invade natural areas throughout northern Virginia and unfortunately, they don’t bother to observe jurisdictional boundaries. In the past, Arlington County and other land management organizations have treated the problem based on their property boundaries with inconsistencies from one neighboring area to the next. Cooperative partnerships across jurisdictions could help to ameliorate this issue, leading to collaborative management within the region and opportunities to leverage resources for large-scale projects.

Cooperative Weed Management Areas, or CWMAs, were created to deal with this problem. A CWMA is a partnership of federal, state, or local government agencies, individuals and various other stakeholders that manage invasive plants in a defined area. Stakeholder groups might include private landowners, non-profit organizations and volunteer groups. The Midwest Invasive Plant Network’s CWMA Cookbook outlines 6 characteristics of CWMAs:

  1. They operate within a defined geographic area, distinguished by a common geography, weed problem, community, climate, political boundary or land use.
  2. They involve a broad cross-section of landowners and natural resource managers within the CWMA boundaries.
  3. They are governed by a steering committee.
  4. They have a long-term commitment to cooperation, usually through a formal agreement among partners.
  5. They have a comprehensive plan that addresses the management of invasive species within their boundaries.
  6. They facilitate cooperation and coordination across jurisdictional boundaries.

There are many advantages that come with the formation of a CWMA; these include sharing resources and information, additional funding opportunities including grants and donations, dealing with Early Detection, Rapid Response species and building community awareness and support. CWMAs are common throughout the country, but are just starting to be formed in our area. The first (and only) CWMA in Virginia was the Potomac Highlands CWPMA, while the DC Cooperative Weed Management Area was formed in the District of Columbia in 2008.

5aThe Potomac Highlands Cooperative Weed and Pest Management Area serves Grant, Hardy and Pendleton Counties in West Virginia and Highland County in Virginia. The mission of Potomac Highlands CWPMA is the prevention and management of invasive species in the headwaters region of the South Branch of the Potomac River in West Virginia and Virginia.

DC Cooperative Weed ManagementThe DC Cooperative Weed Management Area’s mission is to restore natural habitats and ecosystems and to protect biodiversity by working to eliminate invasive plants in DC through a coordinated effort across political and ecological boundaries. Partners include the District Department of the Environment and Department of Parks and Recreation, the National Park Service, the University of the District of Columbia, several non-profit organizations and others.

So how would Arlington form a CWMA? The first step would be to identify possible partners around shared goals for invasive plant management. It is also important to identify a “champion” to spearhead the effort. To formalize the group, a Memorandum of Understanding must be created and signed by all of the partners.  Initial discussions have started with other jurisdictions in northern Virginia, it is possible we may have our own CWMA in the next few years!

Invasive Plant Removal Project Update: Lucky Run/Shirlington Park

If you live in south Arlington, near Shirlington, you may have noticed crews working out near Four Mile Run over the past several months. This work is part of a Neighborhood Conservation (NC) Project that will continue through 2020.

Project Background

Last winter, Arlington County CPHD (Community Planning and Housing Development) in conjunction with DPR (Department of Parks and Recreation) started a Neighborhood Conservation (NC) project along Four Mile Run and Lucky Run and in areas of Shirlington and Allie Freed Parks. This project was approved by Fairlington/Shirlington Civic Association as part of the Fall 2014 funding round for NC projects. The general area is between Walter Reed Drive and Shirlington Road and in areas in Lucky Run and Allie Freed Park. This project has several goals: removal of invasive plant material such as kudzu; establishment of native trees and shrubs for bird and wildlife habitat; and enhancement of the aesthetic quality in the park for both home owners and trail users.

As part of this project, a private company is treating invasive plants using power equipment and herbicide application. The contractors use a glyphosate-based herbicide that is formulated for use near water in natural areas. The winter treatment included the cutting and treating of invasive shrub and vine species as well as smaller invasive trees. The treatment of larger invasive trees will be phased in over several years, to lessen the possibility of erosion.

Target Species

Target species for this project include several high-threat invasive plants; including kudzu, Java dropwort and Japanese knotweed.

Photo: James Miller


Kudzu, Pueraria montana, is one of Arlington’s worst invasive plants.  It is not as widespread as some of our other invasive vine species, but it is the most destructive.  Kudzu is a deciduous twining vine that forms dense infestations along forest edges. It is in the legume family and has violet “pea-like” flowers and flat pods in the fall.

Java Dropwort

Java Dropwort, or Oenanthe javanica, is an aquatic perennial with an aggressive creeping growth habit.  It can grow to a height of 1 to 2 feet in moist areas.  This plant resembles celery in shape and size and has an odor like carrot tops. Java dropwort has medicinal and culinary uses, but can quickly spread in natural areas.

This species is considered an “Early Detection, Rapid Response” species in Arlington because it has only been found in three locations.  The infestation in Lucky Run is definitely the largest in the County, so this project presents a great opportunity to eradicate this species from Arlington.

Photo: Karla Jamir

Photo: Karla Jamir

Japanese Knotweed

Japanese knotweed, or Fallopia japonica, was probably introduced into the United States from eastern Asia in the late 1800s. This plant was first used as an ornamental, but was also planted for erosion control and landscape screening.  Japanese Knotweed is extremely aggressive and poses a significant threat to riparian areas. This plant is an upright, shrubby, herbaceous perennial. It can grow to 4-10 ft. tall and has a large underground rhizome, making it difficult to control.

If you would like more information about this project, please contact

Photo: James Miller

Photo: James Miller

Updates to State Regulations and Resources on Invasive Plants

There are two exciting updates on the state level relating to invasive plants: a new regulation preventing the spread of noxious weeds and a comprehensive list of invasive plants in Virginia.

Noxious Weed Law

The Department of Agriculture and Consumer Services (VDACS) added several invasive species to be regulated under the Virginia Noxious Weeds Law. The new regulation also called for the creation of a Noxious Weeds Advisory Committee for the purpose of assisting VDACS in the evaluation and risk-assessment of plants that may be declared noxious weeds in Virginia.

The new regulation establishes two tiers of noxious weeds. Here are the specifics from the new law:

Tier 1: Any noxious weed that is not native to the Commonwealth that (i) has no known populations present in the Commonwealth or (ii) is not widely disseminated in the Commonwealth and for which successful eradication or suppression is likely.

The following plants are hereby declared Tier 1 noxious weeds:

  1. Vitex rotundifolia, Beach vitex.
  2. Salvinia molesta, Giant salvinia.
  3. Solanum viarum, Tropical soda apple.
  4. Heracleum mantegazzianum, Giant hogweed.
  5. Oplismenus hirtellus spp. undulatifolius, Wavyleaf basketgrass.

Tier 2: Any noxious weed that (i) is not native to the Commonwealth, (ii) is not widely disseminated in the Commonwealth and (iii) for which successful suppression is feasible but eradication is unlikely (3 species).

The following plants are hereby declared Tier 2 noxious weeds:

  1. Imperata cylindrica, Cogon grass.
  2. Lythrum salicaria, Purple loosestrife.
  3. Ipomoea aquatica, Water spinach.

For more information about the new Noxious Weed Law, click here.

Virginia Invasive Species List

9The second updated resource on invasive plants is the new Virginia Invasive Species List.  This list is put out by the Virginia Department of Conservation and Recreation’s (DCR) Natural Heritage Program. Although this list has no regulatory authority, it is a great resource for homeowners and land managers alike. This list ranks various species to reflect the level of threat to forests and other natural communities and native species. DCR’s list was put together using a risk-assessment protocol to determine an invasiveness rank for each species listed, from high to low threat. Another good thing about this list is that it separates out three Virginia ecoregions, included mountain, coastal and piedmont. Certain species, such as beach vitex, have shown to be problematic in coastal areas, but not here in Arlington.

The updated Invasive Plant Species List also includes species that may not be widespread in Virginia but are known to problematic in similar environments. These species are listed under the “early-detection” species. Although Arlington County has been working with nearby jurisdictions to manage these species before they become established, it is great to have a statewide perspective of new invasive plants that we should keep an eye out for.

Letting it R.i.P in Arlington County – Volunteer Opportunities to Remove Invasive Plants


Volunteers at Long Branch Nature Center

Working with volunteers to remove invasive plant species is one of many strategies we use in the battle to protect Arlington’s remaining natural resource areas. In some cases, cutting or pulling invasive plants is the easiest and most effective way to remove them. There are many ways to get involved in volunteer invasive plant removal activities. Beyond protecting wildlife habitat, these volunteer opportunities also offer citizens opportunities to learn about nature, get outside, engage with neighbors, and even get a work out!

Arlington County’s Natural Resources Management Plan highlights the best role for volunteers in removing invasive plants. Activities include:

  • Working in small neighborhood sites where 90-100 percent removal of all invasive plants is an achievable goal, and help educate neighbors about invasive plants.
  • Slowing the spread of invasive plants in target areas by cutting vines back from trees and removing seed and fruit from select species.
  • Providing maintenance-level plant removal after vendors or County staff have completed their work.
  • Providing preventive monitoring and spot removal in sites that are ecologically significant and have not yet been impacted by invasive plants.
  • Monitoring pre-selected target areas and serve as a quick reaction force to eliminate newly established plants before they spread.

Remove Invasive Plants

Beginning in 2005, the County’s volunteer Remove Invasive Plants (RiP) Program was established to enable volunteers to remove invasive plants from County parks. As of 2015, the program has grown to include seven regularly scheduled monthly events at local parks. RiP program volunteers contribute more than 2,000 hours annually to the restoration of County parks.

Adopt a Spot

7aAnother way to get involved with volunteering in Arlington is to sign up through the Adopt a Park program.  Volunteers or groups can adopt parks, streams or even individual trees! To remove invasive plants, volunteers can Adopt a Spot within a park. These volunteers conduct a site visit with County staff to get training on invasive plant identification and removal techniques.

Join a Volunteer Group

Finally, there are many groups that help remove invasive plants at various parks around Arlington County.

Arlington Regional Master Naturalists

The Arlington Regional Master Naturalist (ARMN) chapter of the Virginia Master Naturalist Program is an all-volunteer organization of trained and certified members who serve as officers and administer the program at the local level. Their Mission is to provide environmental education, research, citizen science, outreach, and stewardship of Virginia natural resources and public lands, using ARMN trained and certified volunteers. ARMN members have started volunteer efforts to remove invasives from several County parks, including Barcroft, Bailey’s Branch, Lucky Run, Tuckahoe and others.

TreeStewards of Arlington/Alexandria

TreeStewards are volunteers who take the lead within their communities to enhance a sustainable urban forest through volunteer activities and public education programs. Their chapter took root in 2001, with help from Virginia Cooperative Extension and the Virginia Urban Forestry Council’s Trees Virginia. TreeStewards have helped with invasive plant removal in Lacey Woods, Bluemont Junction, and Nauck Woods.

Master Gardeners of Northern Virginia

Master Gardeners of Northern Virginia (MGNV) is an organization of volunteers who work with the staff of Virginia Cooperative Extension (VCE) to encourage and promote environmentally sound gardening practices. MGNV members must complete over 60 hours of combined classroom and in the field training, as well as 60 hours of volunteer work as interns to become certified by Virginia Tech as VCE Master Gardeners. MGNV support volunteer efforts across the County, and maintain native plant demonstration gardens in Bluemont, Bon Air and several libraries.

For more information on volunteering to remove invasive plants in Arlington, please contact Sarah Archer at

Wanted: Dead or Alive – Using Early Detection, Rapid Response to Manage New Invasive Plant Species

The best way to deal with new invasive plant species is to eradicate them before they have a chance to become established. As a result, Arlington County’s Department of Parks and Recreation has developed an Early Detection, Rapid Response (EDRR) Program. This program provides a framework for managing new threats as they arise. The goal of any EDRR program is to raise awareness about new invaders in order to identify and treat any occurrences before they spread.

EDRR Species

How do we know which new alien plant species are likely to pose a threat to our natural areas? Luckily, the National Park Services’ Center for Urban Ecology (CUE) has researched and developed fact sheets for EDRR species in our region. They have identified 34 species that are considered to be emerging threats. Several of these species, including Thorny Olive, Leatherleaf Mahonia and Fountain Grass have all been documented and treated in Arlington County.

Wavyleaf Basketgrass

The best example of an EDRR Species in our region is Oplismenus hirtellus
, or Wavyleaf Basketgrass. Wavyleaf Basketgrass has not been documented in Arlington County. However, the plant species has been found in Great Falls Park in Maryland, Fraser Preserve and other locations in Fairfax County. For more information about Wavyleaf Basketgrass’ distribution, please check out EDDMapS.

Wavyleaf Basketgrass is very easy to identify because of its similarities to Japanese Stiltgrass, a common invasive plant in Arlington. The only exception is that the plant has rippled leaves. It is low-growing and can be hand-pulled. It’s important to remove the species before it goes to seed because the seeds are extremely sticky and can be spread easily.

How You Can Help

Residents can get involved by learning identification techniques for EDRR species. Some of these species are still available through nurseries and garden centers. It is possible you or your neighbor may have an EDRR species in your home landscape. Engaging in a discussion with your neighbors might be the first step in identifying an EDRR.

Volunteers can help with surveying and mapping these problem species in parks throughout the County. One tool for online mapping is the Mid-Atlantic Early Detection Network (MAEDN) App, which can be downloaded for free. The app allows users to access species information and photographs in the field. Additionally, users can input data on the infestation, add photographs and record a GPS point in the report.  These reports are then verified by a local expert and are communicated with regional land managers.

Volunteers can also assist in the rapid removal of these species on park land and other open space. Many of these species can be carefully eradicated by hand removal techniques. Contact 703-228-1862 about volunteer removal opportunities.

Weevils on the Loose

Arlington has recently acquired a new tool in the battle against invasive plants — weevils. Rhinoncomimus latipes, otherwise known as the mile-a-minute weevil, has been found in several locations around the County. Although the weevil was not released in Arlington, it has traveled here from nearby jurisdictions such as Fairfax County or Washington, D.C. In the past few years, these jurisdictions have released small populations of the mile-a-minute weevil into parkland. The weevils are a form of biological control for Persicaria perfoliata, a particularly aggressive invasive vine otherwise known as mile-a-minute weed.

Mile-a-Minute Weed

Mile-a-minute weed. Photo courtesy of Dr. John Meade, weed scientist emeritus, Rutgers NJAES Cooperative Extension.

About Mile-a-Minute Weed

The Department of Parks and Recreation (DPR) has identified infestations of mile-a-minute in several parks and natural areas. These locations include Windy Run Park, Long Branch Nature Center, Bluemont Park and others. Mile-a-minute weed is an annual, herbaceous vine with prickly stems and triangular leaves. Like its name suggests, this vine can grow very quickly, and will often climb over other plant and up into the tree canopy. Mile-a-minute can create up to 2,000 seeds per plant and spreads into other park areas, causing impacts to the negative vegetation.

Mile-a-Minute WeevilAbout the Mile-a-Minute Weevil

In 2004, the U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS) approved the release of the mile-a-minute weevil in the U.S. The New Jersey Department of Agriculture began mass rearing the weevil in 2004 and the first release was made in Delaware that same year. Years of research were done by APHIS, and other organizations to ensure that mile-a-minute would be the only host plant for the mile-a-minute weevil.

The weevils can be observed directly in the field and are usually spotted on the terminal leaves of a plant. The adults are about 2 millimeters long and are black. Later in the season, they may be covered by an orange film that appears after they have started feeding. The feeding damage on the leaves and stems is also a good way to find out if the weevils are present.

Impact on Mile-a-Minute Weed

Research has shown that the weevils don’t necessarily kill the mile-a-minute plants, but delay seed production and stunt the plants by causing more branching of the stems. The weevil damage allows other plants to compete with mile-a-minute more effectively. DPR has started a pilot management program at Fort C.F. Smith in a meadow area infested with mile-a-minute. Weevils were found at the site this summer. Planting native plants, such as goldenrod, will, in addition to the damage caused by the weevil, minimize the growth rate and seed production of mile-a-minute. Next season, we will be able to see what effect the weevil and other management techniques had in this site.

Ballston Pond Invasive Plant Management

In 2012, the Ballston Pond Invasive Plant Management Project was initiated by the Department of Environmental Services in coordination with the Department of Parks and Recreation. The goal of the project is to contribute to the ecological health of the pond by eliminating, to the extent possible, invasive plants that harm the local ecology and to lay the groundwork for maintaining the pond in an invasive-free state for future generations.

What Is an Invasive Plant?

The 1999 Federal Executive Order on Invasive Species defines an invasive species as a species that’s not native to a particular ecosystem and whose introduction does or is likely to cause economic or environmental harm or harm to human health (Code of Virginia §2.2- 220.2). Invasive plants dominate new areas because they’re without the natural controls that would keep down population in their native settings. Some of the negative impacts to natural areas include degradation of ecosystem health and displacement of native plant species, which provide important habitat and food source for wildlife.

Three invasive plant species have been targeted for management in Ballston Pond:


Alligatorweed. Photo courtesy of U.S. Fish & Wildlife Service.

Alligatorweed – Alternanthera philoxeroides

Appearance: Emergent or rooted floating plant with opposite, elliptical leaves that are up to 4 inches long. Flowering occurs during the summer with white, clover-like heads.

Ecological Threat: Roots in wet soils or shallow water and grows out into waterways. The thick mats can displace native vegetation and wildlife habitat, clog waterways, restrict oxygen levels of water, increase sedimentation, interfere with irrigation and prevent drainage.

Water primrose

Water primrose. Photo courtesy of

Water Primrose – Ludwigia peploides

Appearance: Perennial herbaceous plant of wetlands whose sprawling stems usually grow flat along mud or the surface of the water. Leaves are alternately arranged and range from 0.5-4 inches. Solitary flowers have five yellow petals, 0.4-0.6 inches (1-1.5 centimeters) long.

Ecological Threat: Forms dense, fast-growing, floating mats that can displace native aquatic plants, wetland grasses, lower dissolved oxygen and pH of the water, reduce water quality for wildlife, and increase sedimentation.

Purple loosestrife

Purple loosestrife. Photo courtesy of Bill Johnson.

Purple Loosestrife – Lythrum salicaria

Appearance: Erect perennial herb with a square, woody stem usually covered by downy hair; 4-10 feet high, depending upon conditions. Leaves are arranged in pairs or whorls around the stem. It produces a showy display of magenta-colored flower spikes throughout much of the summer.

Ecological Threat: Under favorable conditions, purple loosestrife is able to rapidly establish and replace native vegetation with a dense, homogeneous stand that reduces local biodiversity, endangers rare species and provides little value to wildlife.

What Can You Do?

You can help this effort by identifying and removing invasive exotic plants on your own property. For more information, visit our Invasive Plant Program online, and then click on “Additional Resources.”  There you can download two booklets, “Plant Invaders of Mid-Atlantic Natural Areas,” and “Mistaken Identity?: Invasive Plants and their Native Look-Alikes.”  You can also contact the Invasive Plant Program at 703-228-1862 for more information.