Most gardeners don't set out to destroy habitat, they simply want to add a splash of color to their yard or plant a tree for shade.

What many don't realize, though, is when they buy certain plants, such as butterfly bush or exotic wisteria, they wind up doing more harm than good.

Invasive plants displace naturally occurring vegetation and, in the process, upset nature's balance and diversity, harming the critters that rely on them for food and changing the landscape of a region. Invasive species are very costly to control, taking over native species as they rapidly spread, dispersing seed and colonizing areas quickly, according to the U.S. Fish & Wildlife Service.

Native species, which carry higher wildlife value by providing food and shelter for Mid-Atlantic critters, are often displaced in the competition for sunlight, sometimes leaving animals -- who are already at a disadvantage due to loss of habitat -- homeless and hungry.

Many invasive plants also emerge earlier in the spring, shading out the native plants that need the sun.

Catherine Smith, owner of Redbud Native Plant Nursery in Glen Mills, Pa., said native plants offer immeasurable benefits over non-natives.

Environmentalists prefer native plants because they require less watering, less maintenance and require no fertilizers and pesticides, which can run off into streams and cause health problems.

Smith said when Mid-Atlantic gardeners choose plants native to the area, they benefit from choosing ones that are well adapted to the climate and soils -- humid summers, cold winters, temperature and moisture fluctuations, clay, sand and shale.

They also act as nature magnets, attracting hummingbirds and other feathered friends, butterflies, bees and other helpful critters.

Still, Phyllis Windle, senior scientist and invasive species expert with Union of Concerned Scientists, said everyday gardeners face many challenges when trying to select the right plants.

Loose federal regulations regarding what species can enter the country and the easy access to invasive plants makes things confusing for consumers who just want to add a little color to their lawns.

"What drives me absolutely crazy is we let almost every single species of organism be imported without any oversight," Windle said, saying that only about 100 plants are denied entrance into the United States.

However, many of those federally prohibited species often find their way into the country through illegal Internet sales and auctions, Windle said.

Still, most harmful species are legal, she said.

Despite the negative impact many plants have on the ecosystem, certain detrimental vines, shrubs and trees -- such as bamboo, English ivy, winged burning bush and Norway maples -- are readily available at just about any box store in the area.

---

Slideshows:
Faces Of Invasives | Want Birds, Butterflies? Use These Native Plants

---

So what's a gardener to do?

Plant-Shopping Tips

No name, no business: If your nursery doesn't tell you the scientific name of the plant, you shouldn't shop there, Windle said, because common names aren't adequate in identifying the species.

Large big box stores tend not to be nearly as knowledgeable as native plant nurseries, she added.

Seek native plant experts: Shop at a nursery that is dedicated to offering native plants that are correctly labeled with scientific names, not just common names. Never remove native plants from their natural settings, or support nurseries that do. Only buy nursery-propagated -- never wild-collected -- native plants.

Arm yourself with a list: Regional groups often provide their own lists of plants that present problems or are likely to cause ecological turmoil in the area.

The Plant Conservation Alliance lists species that should be avoided for planting in Mid-Atlantic states.

People concerned with planting invasives can also find a list of plants to avoid and native alternatives here.

Steer clear of wildflower packets: Wildflower seed packets also pose a risk because they aren't regulated, Windle said.

"I think most people in the public would be stunned that that's the case. It's just not common sense the way we go about things," said added.

Environmental Experts: Don't Plant These Species

A group of university and government scientists formed Invasive.org, and put out lists of plants and trees people should not use in their gardens, ponds or lawns.

They, along with many other experts, recommend never using the following plants in the Mid-Atlantic region:

Aquatic Plants
Eurasian watermilfoil (Myriophyllum spicatum), Giant salvinia (Salvinia molesta), Hydrilla (Hydrilla verticillata), Parrot feather watermilfoil (Myriophyllum aquaticum), Water chestnut (Trapa natans)

Herbaceous Plants
Garlic mustard (Alliaria petiolata), Japanese knotweed (Polygonum cuspidatum), Japanese stiltgrass (Microstegium vimineum), Lesser celandine (Ranunculus ficaria), Purple loosestrife (Lythrum salicaria), Bamboos, exotic (Bambusa, Phyllostachys and Pseudosassa species), Canada thistle (Cirsium arvense), Chinese lespedeza (Lespedeza cuneata), Chinese silver grass (Miscanthus sinensis), Common daylily (Hemerocallis fulva), Common reed (Phragmites australis), Giant hogweed (Heracleum mantegazzianum), Giant reed, wild cane (Arundo donax), Marsh dewflower (Murdannia keisak), Spotted knapweed (Centaurea biebersteinii)

Shrubs
Autumn olive (Elaeagnus umbellata), Bush honeysuckles, exotic (Lonicera species), Japanese barberry (Berberis thunbergii), Multiflora rose (Rosa multiflora), Privets (Ligustrum species), Wineberry (Rubus phoenicolasius), Winged burning bush (Euonymus alata), Butterfly bush (Buddleja species), Japanese spiraea, Japanese meadowsweet (Spiraea japonica), Jetbead (Rhodotypos scandens)

Trees
Bradford pear (Pyrus calleryana 'Bradford'), Norway maple (Acer platanoides), Princess tree (Paulownia tomentosa), Tree of Heaven (Ailanthus altissima), Silk tree, mimosa tree (Albizia julibrissin), Paper mulberry (Broussonetia papyrifera), Sawtooth ok (Quercus acutissima), White mulberry (Morus alba)

Vines
English ivy (Hedera helix), Kudzu (Pueraria montana v. lobata), Mile-a-minute (Polygonum perfoliatum), Oriental bittersweet (Celastrus orbiculatus), Porcelainberry (Ampelopsis brevipedunculata), Wisterias, exotic (Wisteria sinensis, W. floribunda), Creeping euonymus (Euonymus fortunei), Five-leaved akebia (Akebia quinata), Japanese honeysuckle (Lonicera japonica), Louis' swallowwort (Cynanchum louiseae), Periwinkle (Vinca minor)

Recommended Native Plants

The good news is there are tons of plants native to the Mid-Atlantic region that grow well and have high wildlife value.

The Pennsylvania Department of Conservation and Natural Resources offers an extensive online section listing many recommended native plants for different soil types and levels of sunlight.

Some recommended flowers include: Butterfly-weed (Asclepias tuberose), Joe-Pye weed (Eupatorium fistulosum), Bee-balm (Monarda didyma), Bloodroot (Sanguinaria Canadensis), Oxeye sunflower (Heliopsis helianthoides), Beard-tongue (Penstemon digitalis), Black-eyed Susan (Rudbeckia hirta), Cardinal flower (Lobelia cardinalis) and Wild columbine (Aquilegia canadensis), among many others.

Recommended small trees and shrubs include: Serviceberry (Amelanchier arborea) and Flowering dogwood (Cornus florida), Redbud (Cercis canadensis), Wild hydrangea (Hydrangea arborescens), Elderberry (Sambucus canadensis), among many others.

Red maple (Acer rubrum), sugar maple (Acer saccharum), Tulip poplar (Liriodendron tulipfera), Chestnut Oak (Quercus Montana), American beech (Fagus grandifolia), Eastern white pine (Pinus strobes) and River birch (Betula nigra) are among native trees recommended for planting in the area. For a complete list of recommended trees, click here.

DCNR also lists native ferns and grasses.

Cost Of Invasive Takeover

The cost of having invasive plant species take over the landscape is relative to people's beliefs.

For some, losing plants that have been in the region for centuries to a foreign invader is costly enough in itself.

But when plants that don't naturally belong here start wiping out native plants that are unique to the region, the economy is affected, as well.

"I hate to see the same few weedy species taking over," Windle said. "I really don't want to see every national park, state park or local preserve looking alike," Windle said.

Neither do many other people. If there's nothing unique about a certain area, eco-tourists are less likely to visit.

"People don't want to visit a place just like they have at home, covered in dandelions or Queen Anne's lace or teasel," Windle said.

Roger McChesney, Park Manager of Ridley Creek State Park in Delaware County, said plants like multiflora rose, autumn olive, privet, winged euonymus, bush honeysuckle, garlic mustard, Japanese stiltgrass, oriental bittersweet, Japanese honeysuckle, and mile-a-minute are distributed throughout the park.

"Many of these plants are so well established and wide spread that control is not feasible," McChesney said. "Our park policy is to exercise control measures in selected areas based on the use of that area, and the perceived need for elimination or control."

Examples include mowing play fields and picnic areas, clearing walking trails and trying to eradicate invasive species in small areas, like McChesney and volunteers are trying to do with Japanese knotweed along Ridley Creek.