Plant Invaders

All living things - bacteria, fungi, plants, animals and other organisms - have evolved to live in specific areas on the Earth. Local climate, geology, soils, available water and other natural factors influence which plants and animals live in particular ecosystems and habitats.
Natural areas are wild to semi-wild areas such as fields, forests, streams and wetlands that are composed of native plants, animals and microorganisms. A native species is one that occurs naturally in a particular place without human intervention.

Non-native plants are species that have been introduced to an area by people from other continents, states, ecosystems and habitats. Many non-native plants have great economic value for agriculture, forestry, horticulture and other industries and pose little to no threat to our natural ecosystems. Others have become invasive and pose a serious ecological threat.

Kudzu, "The vine that ate the south". USGS photo
Kudzu "The vine that ate the south". USGS photo.

Invasive plants reproduce rapidly, spread over large areas of the landscape and have few, if any, natural controls, such as herbivores and diseases, to keep them in check. Many invasive plants share some important characteristics that allow them to grow out of control.

Like an invading army, invasive plants are taking over and degrading natural ecosystems. Some invasives spread so rapidly that they muscle out most other plants, changing a forest, meadow, or wetland into a landscape dominated by one species. Such "monocultures" (stands of a single plant species) have little ecological value and greatly reduce the natural biological diversity of an area.

Invasive plants also affect the type of recreational activities that we can enjoy in natural areas such as boating, bird watching, fishing and exploring. Once established, invasive plants require enormous amounts of time, labor and money to control or eliminate. Invasive species cost the United States an estimated $34.7 billion each year in control efforts and agricultural losses.

Become familiar with invasive plant species in your area. When selecting plants for landscaping, avoid using known invasive plants. If you already have invasives on your property, consider removing them and replacing them with native species.

Here are few troublesome plants to avoid:

Instead of: purple loosestrife (Lythrum salicaria)
Plant these native alternatives: blazing star (Liatris spicata), New York ironweed (Vernonia noveboracensis), obedient plant (Physostegia virginiana), Joe Pye weed (Eupatorium dubium)

Purple loosestrife. Blazing star. Photo by Randy Loftus, USFWS
Obedient plant. Jennifer Anderson @ USDA-NRCS PLANTS Database
Left: Purple loosestrife (invasive). Photo by Britt Slattery, USFWS. Upper right: Blazing star (native). Photo by Randy Loftus, USFWS. Lower Right: Obedient plant (native). Photo by Jennifer Anderson @ USDA-NRCS PLANTS Database

Instead of: Chinese wisteria (Wisteria sinensis) and Japanese wisteria (Wisteria floribunda)
Plant these native alternatives: American wisteria (Wisteria fructescens), trumpet creeper (Campsis radicans), trumpet honeysuckle (Lonicera sempervirens)

Instead of: English ivy (Hedera helix) and Japanese Pachysandra (Pachysandra terminalis)
Plant these native alternatives: alum root (Heuchera americana), white wood aster (Eurybia divaricata), foam flower (Tiarella cordifolia), partridgeberry (Mitchella repens)

Left: English ivy (invasive). USDA-NRCS photo. Right: Foam flower (native). Photo by Britt Slattery, USFWS
English ivy (invasive) USDA, NRCS photo.

Instead of: Winged burning bush (Euonymous alata) and Japanese barberry (Berberia thunbergii)
Plant these native alternatives: red chokeberry (Aronia arbutifolia), Virginia sweetspire (Itea virginica), highbush blueberry (Vaccinium corymbosum)

Bradford pear (Pyrus calleryana ‘Bradford’)
Plant these native alternatives: redbud (Cercis canadensis), serviceberry (Amelanchier canadensis), southern arrowwood (Viburnum dentatum), flowering dogwood (Cornus florida)

For more information
The National Park Service and U.S. Fish and Wildlife Service put together a guide “Plant Invaders of Mid-Atlantic Natural Areas.” The color guide describes common invasive plants and alternative native plants to use in place of them. To download a copy, go to www.nps.gov/plants/alien/pubs/midatlantic.

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