MontgomeryParks.org

What's the Problem?

How to Help
Know Your Invasive Plants
Links & More Info

Why Non-Native Invasive Plants are Such a Problem
Most natural communities support a great variety of native plants and animals. Such biodiversity is threatened when a few plant species take over and dominate the herbaceous, shrub, and canopy layers of a forest.

Overly successful NNIs can alter the complex webs of plant/animal associations that have evolved over thousands of years to such a degree plants and animals once familiar to all of us are eliminated. In edge and meadow areas, for example, non-native invasive plant (NNI) monocultures can reduce or destroy butterfly populations that can no longer find the native host plants on which their survival depends. Recent research has shown that pure monocultures of NNIs can alter soil chemistry or disrupt the growth of the mycorrhizal fungi on which healthy forests depend.

Coupled with plant predation by over-abundant herds of white-tailed deer and disturbance caused by such activities as development, erosion, and storms, NNIs are causing significant changes in the composition, structure, and ecosystem function in natural areas.
Non-native species threaten two-thirds of endangered species worldwide, and are considered by most experts to be the second most important threat to biodiversity after outright habitat destruction.

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How to Help

A Comprehensive Approach
The Certified Weed Warrior volunteer force and Special Project Warrior Events are crucial components of our comprehensive approach to reclaiming parkland. Natural Resources Stewardship staff has been aware of the problems posed by non-native invasive plants (NNIs) for many years, and has developed several strategies to deal with them. Including:

• Providing you with the opportunity to make a 100% tax deductible contribution to Save the Trees
• Developing long-range management plans that will enable us to take back parkland from the encroachment of NNIs.
• Building staff and financial resources that will enable us to implement those plans.
• Using staff and contract resources to conduct mechanical, chemical, and cultural control efforts in our best natural areas, as well as in highly visible and urbanized natural areas.
• Training park managers and maintenance personnel to recognize and deal with the invasive plant problem as part of their regular work programs.
• Using GIS technology to locate and map heavy NNI infestations and particularly troublesome plants (such as Japanese knotweed, kudzu, and tree-killing vines).
• Developing prioritized lists of treatment sites concurrent with our mapping efforts.
• Implementing reforestation and habitat restoration projects that include a site preparation phase where NNIs are removed.

Join the Weed Warriors Program

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Know Your Invasive Plants

Some non-native plants that became invasive were introduced to the United States by accident (such as stilt grass, which was used as packing material for Chinese porcelain); but most were brought here because they were attractive landscape plants (Japanese knotweed, porcelain berry, Oriental bittersweet); they were familiar food or medicinal plants for settlers and immigrants (garlic mustard, beefsteak plant, mugwort); they provided quick growing pest free erosion control (kudzu), visual screening (running bamboos), windbreaks (autumn olive), or wildlife food (multiflora rose). Some invasives fit several of these categories.

• NNI Plant Identification PowerPoint Presentation (.pdf, 1.7MB)

A typical non-native invasive (NNI) plant has some or all of the following characteristics:

• Grows fast and matures early.
• Spreads quickly over large areas; thrives in many habitats.
• Reproduces profusely by seed and/or vegetative structures.
• Survives and produces seeds under adverse environmental conditions.
• Has few known diseases or pests, and is difficult to remove or control.

Non-native Invasive Plants List
These plants present the most serious threats to natural areas in Montgomery County, including parkland owned and managed by Montgomery Parks:

Autumn olive – Elaeagnus umbellata Bush honeysuckles – Lonicera spp. (ex. Lonicera japonica ) Canada thistle – Cirsium arvense English ivy – Hedera helix Garlic mustard – Alliaria petiolata Japanese honeysuckle – Lonicera japonica Japanese knotweed – Polygonum cuspidatum or Fallopia japonica Japanese or Vietnamese stilt grass – Microstegium vimineum Japanese barberry – Berberis thunbergii Kudzu – Pueraria montana var. lobata

Lesser celandine – Ranunculus ficaria Mile-a-minute or Devil’s tearthumb – Polygonum perfoliatum Multiflora rose – Rosa multiflora Oriental bittersweet – Celastrus orbiculatus Porcelain berry – Ampelopsis brevipedunculata Tree-of-heaven – Ailanthus altissima Wineberry – Rubus phoenicolasius Wintercreeper or climbing euonymus – Euonymus fortunei Running bamboos – various species

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Links and More Information about Invasive and Native Plants

• NNI Plant Identification PowerPoint Presentation (.pdf, 1.7MB)
• National Park Service - Plant Conservation Alliance “Weeds Gone Wild”
• The Maryland Invasive Species Council
• University of Georgia (great photos)
• Maryland Native Plant Society
• The Nature Conservancy and Global Invasive Species Team
• The National Invasive Species Information Center—USDA  

More information and photos are available from The Invasive Plant Atlas of the United States. A collaborative project between the National Park Service, the University of Georgia Center for Invasive Species and Ecosystem Health, and the Invasive Plant Atlas of New England. The purpose of the Atlas is to assist users with identification, early detection, prevention, and management of invasive plants.

Contact Us

Please contact our Volunteer Coordinator for more information and to register for workdays and classes at mcp-weedwarriors@mncppc-mc.org or call Carole Bergmann at 301-962-1348.

back to top - Last update: May 20, 2013