Invasive Plant Species in Delaware

Invasive Plant Species in Delaware

William A. McAvoy, Botanist, Delaware Natural Heritage Program

June 2001

This list contains 64 species and varieties of alien vascular plants considered to be invasive in the state of Delaware. These species are, or have extreme potential to be detrimental to natural systems, i.e., displace native vegetation and disrupt ecological processes. This list is based on personal knowledge, consultation with knowledgeable individuals, and the literature.

Species highlighted in bold are considered to be the most damaging to natural areas in the state. These species are usually shade tolerant, many have a perennial habit, many reproduce and spread primarily by seed and/or spread rapidly through vegetative means, many occur in a variety of habitat types, and many are currently widespread and abundant in the state or have high potential to become widespread.

The purpose of this list is not regulatory, it is to serve only as a reference, advising those who have an interest in alien plant species in Delaware.

SCIENTIFIC NAME	COMMON NAME	HABIT	HABITAT
Acer platanoides	Norway maple	deciduous tree	Upland forests and slopes
Acer pseudoplatanus	sycamore maple	deciduous tree	Escape from cultivation
Ailanthus altissima	tree-of-Heaven	deciduous tree	Disturbed woods, roadsides, fields
Akebia quinata	five-leaf akebia	woody vine	Cultivated and occasionally escaping
Alliaria petiolata	garlic mustard	biennial herb	Moist woods and floodplains
Ampelopsis brevipedunculata	porcelain-berry	woody vine	Moist woods, slopes and thickets
Arthraxon hispidus	joint-head arthraxon	annual grass	Disturbed areas, edges, old fields, roadsides, ditches
Berberis thunbergii	Japanese barberry	deciduous shrub	Escape from cultivation, woods and thickets
Bidens polylepis	tickseed sunflower	annual herb	Marshes, wet meadows, depressions, ditches
Cabomba caroliniana	Carolina fanwort	aquatic herb	Ponds and quiet waters
Carex kobomugi	sedge	perennial sedge	Planted on coastal dunes
Celastrus orbiculata	Oriental bitter-sweet	woody vine	Woods, floodplains, thickets
Cirsium arvense	Canada thistle	perennial herb	Meadows and old fields
Clematis terniflora	Japanese virgin's-bower	herbaceous vine	Stream and river banks, thickets, moist woods
Commelina communis	Asiatic dayflower	annual herb	Disturbed areas, edges, old fields, roadsides, ditches
Conium maculatum	poison-hemlock	biennial herb	Disturbed areas, edges, old fields, roadsides, ditches
Convolvulus arvensis	field bindweed	herbaceous vine	Meadows and old fields
Duchesnea indica	Indian mock-strawberry	perennial herb	Disturbed areas, edges, old fields, roadsides, lawns
Egeria densa	Brazilian water-weed	aquatic herb	Ponds and quiet waters
Eichhornia crassipes	water hyacinth	aquatic herb	Rare in ponds and quiet waters
Elaeagnus umbellata	autumn olive	deciduous shrub	Woods and thickets
Euonymus alata	winged euonymus	deciduous shrub	Moist woods and slopes
Festuca pratensis	meadow fescue	perennial grass	Disturbed areas, edges, old fields, roadsides, ditches
Galanthus nivalis	snow-drops	perennial herb	Escape from cultivation
Hedera helix	English ivy	woody vine	Thin woods, edges and thickets
Hemerocallis fulva	orange daylily	perennial herb	Floodplains and moist woods
Humulus japonicus	Japanese hop	perennial herb	Disturbed areas, edges, old fields, roadsides, ditches
Humulus lupulus	common hop	perennial herb	Disturbed areas, edges, old fields, roadsides, ditches
Hydrilla verticillata	hydrilla	aquatic herb	Ponds and quiet waters
Iris pseudacorus	yellow iris	perennial herb	Fresh water tidal marshes
Leucojum aestivum	summer snowflake	perennial herb	Escape from cultivation
Ligustrum vulgare	European privet	deciduous shrub	Woods and thickets
Lonicera japonica	Japanese honeysuckle	woody vine	Woodlands throughout the state
Lonicera maackii	amur honeysuckle	deciduous shrub	Woods, thickets, old fields, edges
Lonicera morrowii	Morrow’s honeysuckle	deciduous shrub	Woods, thickets, old fields, edges
Lonicera tatarica	Tartarian honeysuckle	deciduous shrub	Woods, thickets, old fields, edges
Ludwigia peploides ssp. glabrescens	floating seedbox	perennial herb	Ponds, slow shallow streams, impoundments, ditches
Lysimachia nummularia	creeping Jennie	perennial herb	Disturbed areas, edges, old fields, roadsides, ditches
Lythrum salicaria	purple loosestrife	perennial herb	Tidal and nontidal marshes, stream banks, wet meadows
Microstegium vimineum	Japanese stilt grass	annual grass	Moist woods and floodplains
Murdannia keisak	marsh dewflower	perennial herb	Marshes, ponds, ditches
Myriophyllum aquaticum	parrot feather	aquatic herb	Ponds and quiet waters
Myriophyllum spicatum	Eurasian water-milfoil	aquatic herb	Ponds and quiet waters
Pachysandra terminalis	pachysandra	perennial herb	Garden escape to woodlands
Phalaris arundinacea	reed canary grass	perennial grass	Fresh and brackish, tidal and nontidal marshes and streams
Phragmites australis	common reed	perennial grass	Widely established in wetlands
Pinus thunbergiana	Japanese black pine	evergreen tree	Coastal dunes
Pistia stratiotes	water lettuce	perennial herb	Rare in ponds and quiet waters
Poa trivialis	rough bluegrass	perennial grass	Disturbed areas, edges, old fields, roadsides, ditches
Polygonum caespitosum	tufted knotweed	annual herb	Disturbed areas, edges, old fields, roadsides, ditches
Polygonum cuspidatum	Japanese knotweed	perennial herb	Roadsides, thickets, thin moist woods, edges
Polygonum perfoliatum	mile-a-minute	annual herb	Thin moist woods, floodplains, swales and marshes
Pseudosasa japonica	bamboo	perennial grass	Edge of woods and roadsides
Pueraria montana	kudzu	herbaceous vine	Roadsides, edges of woods
Ranunculus ficaria	lesser celandine	perennial herb	Floodplains and moist woods
Rhodotypos scandens	jetbead	deciduous shrub	Cultivated and occasionally escaping
Rosa multiflora	multiflora rose	deciduous shrub	Meadows, old fields, thickets, edges
Rubus idaeus ssp. strigosus	red raspberry	deciduous shrub	Old fields, thickets, edges, hedgerows
Rubus phoenicolasius	wineberry	deciduous shrub	Disturbed areas, edges, old fields, roadsides, ditches
Sorghum halepense	Johnson grass	perennial grass	Crop land, meadows, moist swales
Trapa natans	water chestnut	aquatic herb	Rare in ponds and quiet waters
Urtica dioica	stinging nettle	perennial herb	Disturbed areas, edges, old fields, roadsides, ditches
Vinca minor	periwinkle	perennial herb	Thin woods, edges and thickets
Wisteria floribunda	Japanese wisteria	woody vine	Roadside thickets and abandoned gardens, old homesites