For help in identification of invasive plants, treatment, and protection suggestions for your property, explore the DCNR fact sheets below.
DCNR has deemed these trees, shrubs, vines, herbs, and aquatic plants to be invasive on state lands. The species listed are managed by DCNR staff.
Trees
- Amur maple (PDF)(opens in a new tab), Acer ginnala, is a small ornamental tree that spreads by numerous winged seeds.
- Norway maple (PDF)(opens in a new tab), Acer platanoides, a common street and lawn tree that frequently escapes cultivation.
- Sycamore maple (PDF)(opens in a new tab), Acer pseudoplatanus, a tall Eurasian tree invading urban and suburban woods in southern Pennsylvania.
- European black alder (PDF)(opens in a new tab), Alnus glutinosa, is often found along streams and other wet areas.
- Tree-of-heaven (PDF)(opens in a new tab), Ailanthus altissima, grows throughout Pennsylvania. Another immigrant from China introduced as an ornamental.
- Mimosa (PDF)(opens in a new tab), Albizia julibrissin, has escaped cultivation to invade roadsides and woodland edges in eastern Pennsylvania.
- Japanese angelica tree (PDF)(opens in a new tab), Aralia elata, has sharp spines on the trunk and resembles our native devils walking stick.
- Paper mulberry (PDF)(opens in a new tab), Broussonetia papyfera, is a common, small ornamental tree from Asia.
- White mulberry (PDF)(opens in a new tab), Morus alba, is a fast-growing species that will hybridize with our native red mulberry, Morus rubra.
- Princess-tree, empress-tree (PDF)(opens in a new tab), Paulownia tomentosa, imported from China this purple-flowered tree has spread across southern Pennsylvania by winged seeds.
- Cork tree (PDF)(opens in a new tab), Phellodendron amurense, P. japonicum, P. lavallei, these Asian trees are problematic in urban and natural areas in southeastern Pennsylvania.
- Callery or bradford pear (PDF)(opens in a new tab), Pyrus calleryana, has established populations in fields and hedgerows in southeastern Pennsylvania.
- Bee-bee tree (PDF)(opens in a new tab), Tetra dium daniellii, is an uncommon landscape tree that is slowly spreading in southcentral and southeastern Pennsylvania.
- Siberian elm (PDF)(opens in a new tab), Ulmus pumila, a fast-growing tree reaching 50-70 feet high.
Shrubs
- European and Japanese barberries (PDF)(opens in a new tab), Berberis vulgaris and B. thunbergii form dense thickets in woodlands, wetlands, and meadows.
- Butterfly bush (PDF)(opens in a new tab), Buddleja davidii, has numerous cone-shaped bunches of purple flowers that attract butterflies.
- Russian olive and autumn olive (PDF)(opens in a new tab), Elaeagnus angustifolia and E. umbellata, imported from Asia, have become serious weeds in southern Pennsylvania pastures and other open ground.
- Winged euonymus or burning bush (PDF)(opens in a new tab), Euonymus alatus, a shrub from China and Japan imported for its bright purple-red fall color and frequently found along streams and in woods mostly in southern Pennsylvania.
- Chinese and shrubby bushclovers (PDF)(opens in a new tab), Lespedeza cuneata and L. bicolor, are semi-woody shrubs that readily invade open and disturbed habitats.
- Privets (PDF)(opens in a new tab), Ligustrum species, imported from Europe and Asia are aggressive, thicket forming shrubs.
- Shrub honeysuckles (PDF)(opens in a new tab), five Lonicera species that rapidly invade and dominate field edges and pastures.
- Common buckthorn (PDF)(opens in a new tab) and Glossy buckthorn (PDF)(opens in a new tab), Rhamnus cathartica and R. frangula, are small trees or shrubs to 20-feet high with yellow sapwood and pink to orange heartwood.
- Jetbead (PDF)(opens in a new tab), Rhodotyposscandens, is a deciduous shrub with clusters of small black fruits and white four-petaled flowers.
- Multiflora Rose (PDF)(opens in a new tab), Rosa multiflora, this import from Asia has become a noxious weed in Pennsylvania fields, pastures, and woodlands.
- Wineberry (PDF)(opens in a new tab), Rubus phoenicolasius, imported from Asia for its raspberry-like fruit and now common on roadsides and in woods and thickets.
- Japanese spiraea (PDF)(opens in a new tab), Spiraea japonica, was imported from Japan for its pink flowers. It escapes from cultivation to forest openings and meadows.
- Doublefile viburnum (PDF)(opens in a new tab), Viburnum plicatum; Linden viburnum (PDF)(opens in a new tab), V.dilataum; and Siebold viburnum (PDF)(opens in a new tab), V. sieboldii, are Asian shrubs with abundant fruits that are spread by birds.
- Guelder rose (PDF)(opens in a new tab), Viburnum opulus, a tall shrub with maple-like leaves imported from Eurasia and escaped to woods fields and roadsides.
Vines
- Chocolate vine (PDF)(opens in a new tab), Akebia quinata, a woody twining vine from Asia that has escaped cultivation to disturbed woods in southeastern Pennsylvania.
- Porcelain berry (PDF)(opens in a new tab), Ampelopsis brevipedunculata, a deciduous, woody, perennial vine in the grape family imported from Asia.
- Oriental bittersweet (PDF)(opens in a new tab), Celastrus orbiculatus, a twining woody vine imported from Asia and rapidly replacing the native bittersweet in the woods.
- Winter creeper (PDF)(opens in a new tab), Euonymus fortunei, is an evergreen woody vine that aggressively invades forest edges and openings.
- English ivy (PDF)(opens in a new tab), Hedera helix, is a common evergreen climbing vine in the landscape that can smother native vegetation.
- Japanese hops (PDF)(opens in a new tab), Humulus japonicus, is a prickly vine that invades moist, sunny areas.
- Japanese honeysuckle (PDF)(opens in a new tab), Lonicera japonica, a common ornamental vine from Asia now an abundant weed in roadside thickets, woods, and fields across southern Pennsylvania.
- Mile-a-minute weed (PDF)(opens in a new tab), Persicaria perfoliata, a slender annual vine with reflexed prickles was accidentally introduced from Asia with nursery stock and now a noxious weed in Pennsylvania.
- Kudzu (PDF)(opens in a new tab), Pueraria lobata, a vigorous half-woody vine introduced from Asia for ornament, forage, and erosion control and now an uncommon but officially noxious weed in southeastern Pennsylvania.
- Common and bigleaf periwinkle (PDF)(opens in a new tab), Vinca minor and V. major, are evergreen, ornamental groundcovers that can form thick mats, even under dense tree canopy.
- Black and pale swallow-wort (PDF)(opens in a new tab), Vincetoxicum nigrum and V. rossicum, are twining vines that can dominate old fields and poison livestock.
- Chinese and Japanese wisteria (PDF)(opens in a new tab), Wisteria sinensis and W. floribunda, are long-lived woody vines with bright purple flowers that can out-compete and smother native vegetation.
Grasses
- Small carpetgrass (PDF)(opens in a new tab), Anthraxon hispidus, is native to Asia. It is currently found in a few counties in southern Pennsylvania, usually alongside invasive stiltgrass.
- Cheatgrass and poverty brome (PDF)(opens in a new tab), Bromus tectorum and B. sterilis, accidentally introduced from Europe in ballast soil or impure wheat seed shipments. A serious agricultural weed in the Midwest and western states.
- Common velvet grass (PDF)(opens in a new tab), Holcus lanatus, introduced as early as the 17th century in imported pasture seed.
- Japanese stiltgrass (PDF)(opens in a new tab), Microstegium vimineum, introduced from tropical Asia in packing material and spreading through moist areas open woods and clearings across southeastern Pennsylvania and probably elsewhere.
- Chinese silvergrass (PDF)(opens in a new tab), Miscanthus sinensis, is a tall bunched grass that spreads through vigorous roots and rhizomes.
- Wavyleaf basketgrass (PDF)(opens in a new tab), Oplismenus undulatifolius, is a fast-growing, creeping grass.
- Reed canary grass (PDF)(opens in a new tab), Phalaris arundinacea, forms dense monocultures in wet habitats that disrupt waterways and degrade habtitat for native wildlife.
- Common reed (PDF)(opens in a new tab), Phragmites australis, a very large perennial grass, forms extensive colonies in wetlands. The scattered native American populations are being replaced by the vigorous European subspecies.
- Golden, yellow groove, and giant timber bamboo (PDF)(opens in a new tab), Phyllostachys aurea, is a very tall grass with round, hollow stems that spreads rapidly via its underground rhizomes.
- Rough bluegrass (PDF)(opens in a new tab), Poa trivialis, is a non-descript grass that out-competes native grasses.
- Ravenna grass (PDF)(opens in a new tab), Saccharum ravennae, is also known as hardy pampas grass. It grows up to 10-feet tall and quickly colonizes wet habitats.
- Tall fescue (PDF)(opens in a new tab), Schedonorus arundinaceus, is a very common cool season perennial grass that adapts to a variety of conditions and crowds out native vegetation.
- Shattercane and johnsongrass (PDF)(opens in a new tab), Sorghum bicolor, and Sorghum halepense was imported from Africa and the Mediterranean region as a forage crop but is now a noxious weed in Pennsylvania.
Herbs
- Goutweed (PDF)(opens in a new tab), Aegopodium podagraria, imported from Eurasia and frequently found in fields, thickets, woods, and roadsides throughout Pennsylvania.
- Garlic mustard (PDF)(opens in a new tab), Alliaria petiolata, a weed of shady moist spots in suburban gardens, woods, and floodplains throughout Pennsylvania; introduced from Europe.
- Wild chervil (PDF)(opens in a new tab), Anthriscus sylvestris, is a member of the carrot family that competes with native plants and carries a virus that can infect some vegetable crops.
- Narrowleaf bittercress (PDF)(opens in a new tab), Cardamine impatiens, is a member of the mustard family native to Europe.
- Musk thistle (PDF)(opens in a new tab), Carduus nutans, is also known as nodding thistle from the way the flowers droop once mature.
- Black, brown, and spotted knapweeds (PDF)(opens in a new tab), Centaurea nigra, C. jacea, C. stoebemicranthos, have pink to purple flowers that resemble small pineapples.
- Greater celandine (PDF)(opens in a new tab), Chelidonium majus, is a four-petaled yellow flower from Europe that is poisonous.
- Canada thistle (PDF)(opens in a new tab), Cirsium arvense, imported from Eurasia (not Canada) now common and noxious weed in fields pastures and roadsides throughout Pennsylvania.
- Bull thistle (PDF)(opens in a new tab), Cirsium vulgare, is a large-flowered thistle with long spines and abundant seeds.
- Spiny plumeless thistle (PDF)(opens in a new tab), Carduus acanthoides, is a prickly, biennial plant that invades open areas and grasslands.
- Poison hemlock (PDF)(opens in a new tab), Conium maculatum, was brought to United States gardens from Europe in the 1800s and now invades native plant communities in riparian woodlands, open floodplains, and stream banks.
- Crown-vetch (PDF)(opens in a new tab), Coronilla varia, a sprawling perennial native to southern Europe planted extensively along highways. It spreads into open, grassland and prairie habitats.
- Jimsonweed (PDF)(opens in a new tab), Datura stramonium, is a state noxious weed that is highly toxic and frequently found in cultivated fields and other disturbed sites.
- Smallflower and hairy willow herb (PDF)(opens in a new tab), Epilobium parviflorum and E.hirsutum are ornamental perennials with showy, rose-colored flowers that can quickly form dense stands.
- Goats rue (PDF)(opens in a new tab), Galega officinalis, is a state and federal noxious weed that is very poisonous to livestock.
- Orange daylily (PDF)(opens in a new tab), Hemorocallis fulva, is a very hard perennial that grows in abundance along roadsides and old home sites.
- Giant hogweed (PDF)(opens in a new tab), Heracleum mantegazzianum, 15-foot tall member of the carrot family introduced from Eurasia. Its sap can cause blisters so it is listed as a federal and Pennsylvania noxious weed.
- Dame’s-rocket (PDF)(opens in a new tab), Hesperis matronalis, introduced from Europe to American gardens, now common in low woods floodplains and roadside ditches throughout Pennsylvania.
- Yellow flag iris (PDF)(opens in a new tab), Iris pseudacorus, is a showy ornamental plant commonly found in wetlands, along pond edges, and other wet areas where it can dominate.
- Moneywort (PDF)(opens in a new tab), Lysimachia nummularia, goes by many common names and was introduced into the United States from Europe as an ornamental groundcover.
- Purple loosestrife (PDF)(opens in a new tab), Lythrum salicaria, a European perennial with a woody base that has escaped gardens and destroyed large areas of waterfowl habitat by dominating wetlands and excluding all other plant life.
- Star-of-Bethlehem (PDF)(opens in a new tab), Ornithogalum nutans and O. umbellatum, garden bulbs from Europe that escape to infest lawns and roadsides.
- Japanese pachysandra (PDF)(opens in a new tab), Pachysandra terminalis, is an evergreen perennial groundcover that can spread from cultivation into natural areas if left uncontrolled.
- Wild parsnip (PDF)(opens in a new tab), Pastinaca sativa, a European import now a widespread and abundant weed of roadsides throughout Pennsylvania.
- Beefsteak plant (PDF)(opens in a new tab), Perilla frutescens, a member of the mint family introduced from India now occasionally found in moist shaded roadsides and woods.
- Bristled knotweed (PDF)(opens in a new tab), Persicaria longiseta, is an annual plant from Asia that can dominate wet, disturbed habitats.
- Japanese and giant knotweed (PDF)(opens in a new tab), Fallopia japonica and F. sachalinensis, are extremely difficult weeds to control. Imported from Japan, they dominate stream and river banks throughout Pennsylvania.
- Lesser celandine (PDF)(opens in a new tab), Ranunculus ficaria, an aggressive weed in wetlands imported from Eurasia.
Aquatic Plants
- Carolina fanwort (PDF)(opens in a new tab), Cabomba caroliniana, is a submerged, rooted plant native to the southeastern United States and sold for aquariums.
- Didymo (PDF)(opens in a new tab), Didymoshenia geminate, is a microscopic alga called a diatom. It can form dense mats that smother stream beds and native vegetation.
- Brazilian water-weed (PDF)(opens in a new tab), Egeria densa, is a popular aquarium plant that can grow vigorously and choke out native vegetation once it reaches ponds, lakes and other waterbodies.
- Hydrilla (PDF)(opens in a new tab), Hydrilla verticillata, is a submerged aquatic plant that resembles several other aquatic plants, making identification difficult.
- Starry stonewort (PDF)(opens in a new tab), Nitellopsis obtusa, is a freshwater micro-algae native to Europe and Asia.
- Floating primrose-willow (PDF)(opens in a new tab), Ludwigia peploides ssp. glabrescens, is indigenous to slow-moving waters of the southeastern United States and is now found across southern Pennsylvania.
- Parrot feather watermilfoil (PDF)(opens in a new tab), Myriophyllum aquaticum, is an aquarium plant native to South America that can form dense mats in Pennsylvania lakes and ponds.
- Eurasian water-milfoil (PDF)(opens in a new tab), Myriophyllum spicatum, a common an abundant Eurasian invader of lakes and rivers throughout Pennsylvania.
- Curly pondweed (PDF)(opens in a new tab), Potamogeton crispus, an aggressive European weed common in lakes, ponds, and streams.
- Water chestnut (PDF)(opens in a new tab), Trapanatans, a locally abundant Eurasian invader of ponds and lakes.
- Narrow-leaved cattail (PDF)(opens in a new tab), Typhaangustifolia, is from Europe and difficult to visually distinguish from our native cattail.
- Hybrid cattail (PDF)(opens in a new tab), Typhaxglauca, a cross between narrow-leaved cattail and native common.