COMMON NAME
English ivy
FAMILY
Araliaceae
NPS CODE
HEDHEL
NPS NORTHEASTERN STATUS
Potentially invasive
THREAT
Can produce dense, monotypic stands that outcompete other vegetation. Can also climb.
INVASIVE ECOLOGY
Soil adaptable, pH tolerant, somewhat salt tolerant. Dense mat growth habit. Dominates understory, blankets and kills all other vegetation. Fruiting branches are uncommon.
GEOGRAPHIC ORIGIN
Europe, western Asia and north Africa
HISTORY OF INTRODUCTION
Introduced in Colonial times from Europe as an ornamental landscape plant.
NORTHEASTERN US DISTRIBUTION
Entire Northeast except for Maine, Vermont and New Hampshire. May not exist away from sites of intentional human introduction in northern New England.
NORTHEASTERN NATIONAL PARKS
REPRODUCTION
Woody evergreen climber with perennial stems. Reproduces from stem cuttings and will root where the vine touches the ground. Flowers in the fall.
FRUIT AND SEED PRODUCTION
Produce fruits in Spring following flowering; each contains 2 to 5 seeds. Fruits often persist through the winter.
CONTROL
Herbicide, persistent cutting and hand-pulling.
SPECIES NAME
Hemerocallis fulva (L.) L.
COMMON NAME
Orange daylily
FAMILY
Liliacaeae
NPS CODE
HEMFUL
NPS NORTHEASTERN STATUS
Potentially invasive in an anthropogenic landscape.
THREAT
Spreads vegetatively forming dense, monotypic stands.
INVASIVE ECOLOGY
Drought resistant, tolerant of a wide range of soil conditions.
GEOGRAPHIC ORIGIN
East Asia
HISTORY OF INTRODUCTION
Escaped from cultivation in the United States.
NORTHEASTERN US DISTRIBUTION
Entire Northeast
NORTHEASTERN NATIONAL PARKS
DEWA
REPRODUCTION
Perennial forb, flowers June through August. Reproduces vegetatively by spreading rhizomes
FRUIT AND SEED PRODUCTION
Sterile triploid
CONTROL
SPECIES NAME
Heracleum mantegazzianum Sommier & Levier
COMMON NAME
Giant hogweed
FAMILY
Apiaceae
NPS CODE
HERMAN
NPS NORTHEASTERN STATUS
Potentially invasive, on the federal noxious weed list.
THREAT
Produces copious amounts of seed that can give rise to numerous offspring.
INVASIVE ECOLOGY
Can outcompete native species for habitat and causes increased soil erosion.
GEOGRAPHIC ORIGIN
Caucasus Mountains and southwest Asia.
HISTORY OF INTRODUCTION
Introduced as a garden plant to the United States in 1917.
NORTHEASTERN US DISTRIBUTION
Maine, Vermont, Connecticut, New York and Pennsylvania
NORTHEASTERN NATIONAL PARKS
ACAD
REPRODUCTION
Herbaceous biennial or monocarpic perennial flowers from June to July. Seeds dispersed by water or planting by humans as garden ornamentals.
FRUIT AND SEED PRODUCTION
Abundant seed
CONTROL
Herbicides, hand digging, and possibly biocontrol by cattle and pigs
N.B. Has poisonous sap that causes blistering and burns to the skin when exposed to sunlight.
SPECIES NAME
Hesperis matronalis L.
COMMON NAME
Dame’s rocket
FAMILY
Brassicaceae
NPS CODE
HESMAT
NPS NORTHEASTERN STATUS
Invasive
THREAT
Produces many seeds and can form dense stands.
INVASIVE ECOLOGY
Grows well in riparian habitats, rich woodlands and roadsides. Often planted in gardens and along roads. Often thought of as a native wildflower. Crowds out native vegetation and produces a great number of seeds and has a long reproductive season. Dense stands produces great variety of flower colors.
GEOGRAPHIC ORIGIN
Europe
HISTORY OF INTRODUCTION
Introduced to the United States in 1600(?) for garden and medicinal use.
NORTHEASTERN US DISTRIBUTION
Entire Northeast
NORTHEASTERN NATIONAL PARKS
DEWA
REPRODUCTION
Herbaceous biennial or perennial, flowers from May to July. Reproduces vegetatively and from seed.
FRUIT AND SEED PRODUCTION
Seeds dispersed mechanically, sometimes planted as part of a “native” wildflower mix.
CONTROL
Cutting flower heads after they bloom, hand pulling, and herbicide.
SPECIES NAME
Humulus japonicus Sieb. & Zucc.
COMMON NAME
Japanese hops
FAMILY
Cannabaceae
SYNONYMS
Humulus scandens auct. non (Lour.) Merr.
NPS CODE
HUMJAP
NPS NORTHEASTERN STATUS
Invasive
INVASIVE ECOLOGY
Drought tolerant, rapid growth rate. Often seen in dense thickets along river shores and in calcareous wetlands.
GEOGRAPHIC ORIGIN
Eastern Europe
HISTORY OF INTRODUCTION
NORTHEASTERN US DISTRIBUTION
Entire Northeast
NORTHEASTERN NATIONAL PARKS
REPRODUCTION
Annual vine, flowers in midsummer through fall
FRUIT AND SEED PRODUCTION
CONTROL
SPECIES NAME
Hydrilla verticillata (L. f.) Royle
COMMON NAME
Hydrilla
FAMILY
Hydrocharitaceae
NPS CODE
HYDVER
NPS NORTHEASTERN STATUS
Invasive
THREAT
Dense rapid growth can choke water bodies.
INVASIVE ECOLOGY
Grows in still and running water. pH and salinity tolerant, and tolerant of both oligotrophic and eutrophic lakes. Forms dense, monotypic mats that shade and choke out native vegetation. Shade tolerant. Raises pH of water, decreases oxygen and raises water temperature. Causes water to stagnate.
HABITAT
Rivers, lakes and ponds.
GEOGRAPHIC ORIGIN
Uganda and Tanzania
HISTORY OF INTRODUCTION
Introduced to the United States in the 1950s in Florida for use as an aquarium plant. First recorded outside of cultivation in 1960. The first New England record is from Connecticut in 1989.
NORTHEASTERN US DISTRIBUTION
Massachusetts, Connecticut, Pennsylvania, New Jersey, Delaware and Maryland.
NORTHEASTERN NATIONAL PARKS
REPRODUCTION
Submerged, aquatic perennial herb in both monoeceous and dioecious form. Can reproduce vegetatively, by seed, and by stem turion. Dispersed by waterfowl and boats.
FRUIT AND SEED PRODUCTION
CONTROL
Lake drawdowns, mechanical harvesters, biocontrol fish and insects and herbicides. Boaters should clean their boats and trailers before leaving boat ramps.
N.B. Closely resembles native Elodea species.
SPECIES NAME
Hypericum prolificum L.
COMMON NAME
Shrubby St. Johnswort
FAMILY
Clusiaceae
SYNONYMS
Hypericum spathulatum (Spach) Steud.
NPS CODE
HYPPRO
NPS NORTHEASTERN STATUS
Potentially invasive
THREAT
Can produce numerous individuals.
INVASIVE ECOLOGY
Does well in dry, rocky soils, calcareous soils, pH adaptable
GEOGRAPHIC ORIGIN
New Jersey to Iowa
HISTORY OF INTRODUCTION
Introduced around 1750.
NORTHEASTERN US DISTRIBUTION
Entire Northeast
NORTHEASTERN NATIONAL PARKS
ACAD
REPRODUCTION
Deciduous perennial shrub, flowers in July through September. Reproduces by cuttings or seed.
FRUIT AND SEED PRODUCTION
Fruits ripen in September and persist all winter.
CONTROL
SPECIES NAME
Impatiens glandulifera Royle
COMMON NAME
Himalayan jewelweed
FAMILY
Balsaminaceae
SYNONYMS
Impatiens roylei Walp.
NPS CODE
IMPGLA
NPS NORTHEASTERN STATUS
Potentially invasive
THREAT
Can produce a large number of individuals in dense stands.
INVASIVE ECOLOGY
Grows well in a wide range of soil types, partially shade tolerant. Has a fast growth rate. Seeds are abundant (2500 seeds per plant), viable for 18 months after production and are dispersed explosively. Competes for pollinators from natives and produces abundant nectar.
GEOGRAPHIC ORIGIN
Himalayas, India
HISTORY OF INTRODUCTION
Probably as an ornamental
NORTHEASTERN US DISTRIBUTION
Maine, Vermont, New York, Massachusetts
NORTHEASTERN NATIONAL PARKS
REPRODUCTION
Herbaceous annual forb, flowers June through October, reproduces by seed. Dispersal is mechanical or by water.
FRUIT AND SEED PRODUCTION
Up to 800 seeds per capsule.
CONTROL
Herbicide, grazing and hand-pulling
SPECIES NAME
Iris pseudacorus L.
COMMON NAME
Yellow iris
FAMILY
Iridaceae
NPS CODE
IRIPSE
NPS NORTHEASTERN STATUS
Potentially invasive
THREAT
Large numbers of individuals can form dense stands.
INVASIVE ECOLOGY
Grows well in freshwater wetlands, tolerant of high acidity and salinity. Forms large clonal populations that displace native species. Rhizomes survive drought and seeds survive burns. Poisonous to grazing animals and can cause skin irritation to humans.
GEOGRAPHIC ORIGIN
Europe, Caucasus Mountains, western Asia and north Africa
HISTORY OF INTRODUCTION
Introduced to the United States as a garden planting in the mid 1800s. Used for erosion control and in sewage treatment plants.
NORTHEASTERN US DISTRIBUTION
Entire Northeast
NORTHEASTERN NATIONAL PARKS
REPRODUCTION
Herbaceous perennial, flowers from April to June. Seeds are water dispersed. Plants also distributed via rhizomes planted by gardeners. Seeds and rhizomes can disperse downstream.
FRUIT AND SEED PRODUCTION
Fruits contain approximately 120 seeds each.
CONTROL
Mechanical harvesters and herbicides.
SPECIES NAME
Lepidium latifolium L.
COMMON NAME
Tall pepperwort
FAMILY
Brassicaceae
SYNONYMS
Cardaria latifolia (L.) Spach
NPS CODE
LEPLAT
NPS NORTHEASTERN STATUS
Potentially invasive
THREAT
Large numbers of individuals form dense, nearly monotypic stands.
INVASIVE ECOLOGY
Deep-seated rootstocks, forms dense monospecific stands, displaces native plants and animals. Has salt pumping capabilities and is adaptable to a wide range of habitats. Salt tolerance allows the species to grow along the roadside and along the upper edges of salt marshes.
GEOGRAPHIC ORIGIN
Southern Europe and western Asia
HISTORY OF INTRODUCTION
In cultivation by the Harvard Botanic Garden around 1879.
NORTHEASTERN US DISTRIBUTION
Coastal Northeast
NORTHEASTERN NATIONAL PARKS
REPRODUCTION
Herbaceous perennial forb, flowers in early summer to fall.
FRUIT AND SEED PRODUCTION
Fruits mature in late spring through summer. Each fruit contains two seeds. A one-acre infestation can produce over six billion seeds per acre. Dispersed by water, the movement of contaminated soil, via machinery and tires, and by livestock and waterfowl.
CONTROL
Continual flooding, herbicide, and hand-pulling
SPECIES NAME
Lespedeza cuneata (Dum.-Cours.) G. Don
COMMON NAME
Chinese lespedeza
FAMILY
Fabaceae
SYNONYMS
Lespedeza sericea Miq.
NPS CODE
LESCUN
NPS NORTHEASTERN STATUS
Invasive
THREAT
Plants produce large numbers of seeds.
INVASIVE ECOLOGY
Drought tolerant, tolerant of acidic and shallow soil. Crowds out native plants and develops and extensive seed bank. Seeds viable for over 20 years. High in tannin and unpalatable to wildlife and livestock. Can grow in sterile soil. Used in highway “seed mixes” because of its nitrogen-fixing ability.
GEOGRAPHIC ORIGIN
Japan
HISTORY OF INTRODUCTION
Introduced to the southern United States from China for erosion control and soil improvement. Hay facilitated spread to the Northeast.
NORTHEASTERN US DISTRIBUTION
New Jersey, Massachusetts, Connecticut, New Jersey, Pennsylvania, Maryland, Virginia, West Virginia
NORTHEASTERN NATIONAL PARKS
DEWA
REPRODUCTION
Perennial herb, flowers mid June to early October
FRUIT AND SEED PRODUCTION
Reproduces by seed. Seeds dispersed by animals, haying of infested fields and possibly by “hydroseeding” along highways.
CONTROL
Mowing yearly and herbicide
SPECIES NAME
Lespedeza stipulacea Maxim.
COMMON NAME
Korean clover
FAMILY
Fabaceae
SYNONYMS
Kummerowia stipulacea (Maxim.) Makino
NPS CODE
LESSTI
NPS NORTHEASTERN STATUS
Potentially invasive
THREAT
Produces many seeds which give rise to many new plants.
INVASIVE ECOLOGY
Drought resistant, can grow in poor soil, fixes nitrogen, reseeds itself.
GEOGRAPHIC ORIGIN
Japan, Korea, China
HISTORY OF INTRODUCTION
Introduced to the United States in 1919.
NORTHEASTERN US DISTRIBUTION
New York, Pennsylvania, Jew Jersey, Maryland, West Virginia, Virginia
NORTHEASTERN NATIONAL PARKS
REPRODUCTION
Annual legume, flowers in June through September
FRUIT AND SEED PRODUCTION
CONTROL
SPECIES NAME
Ligustrum obtusifolium Sieb. & Zucc.
COMMON NAME
Border privet
FAMILY
Oleaceae
NPS CODE
LIGOBT
NPS NORTHEASTERN STATUS
Invasive
THREAT
Produces copious amounts of seed and can form dense stands.
INVASIVE ECOLOGY
Extremely adaptable, dense, spreads rapidly
GEOGRAPHIC ORIGIN
Japan
HISTORY OF INTRODUCTION
Introduced to the United States in 1860.
NORTHEASTERN US DISTRIBUTION
Entire Northeast except Maine and Vermont
NORTHEASTERN NATIONAL PARKS
DEWA
REPRODUCTION
Semi-evergreen to deciduous shrub, flowers in late May to early June. Reproduces by seed or rhizome.
FRUIT AND SEED PRODUCTION
Fruits ripen in September and persist until spring. Seeds are bird dispersed and occasionally dispersed by water.
CONTROL
Mowing, cutting and herbicide
SPECIES NAME
Ligustrum ovalifolium Hassk.
COMMON NAME
California privet
FAMILY
Oleaceae
NPS CODE
LIGOVA
NPS NORTHEASTERN STATUS
Potentially invasive
THREAT
Can produce dense stands and many offspring.
INVASIVE ECOLOGY
Forms dense thickets, rapid growth rate, shade tolerant, produced abundant seedlings. Sprouts from roots and stumps.
GEOGRAPHIC ORIGIN
Japan
HISTORY OF INTRODUCTION
Introduced as an ornamental
NORTHEASTERN US DISTRIBUTION
Massachusetts, Connecticut, Pennsylvania, New Jersey, Maryland and Virginia
NORTHEASTERN NATIONAL PARKS
REPRODUCTION
Evergreen to semi-evergreen shrub, flowers in July. Reproduces by seeds or roots.
FRUIT AND SEED PRODUCTION
Fruits mature in late summer and fall.
CONTROL
Herbicide, mowing, cutting
SPECIES NAME
Lonicera fragrantissima Lindl. & Paxton
COMMON NAME
Sweet breath of spring
FAMILY
Caprifoliaceae
SYNONYMS
Sylosteon fragrantissimum (Lindl. & Paxton) Small
NPS CODE
LONFRA
NPS NORTHEASTERN STATUS
Potentially invasive
THREAT
Can produce many offspring and form dense thickets.
INVASIVE ECOLOGY
Fast growth rate, easy to grow, adapted to many soils and pH levels, has tremendous shade tolerance
GEOGRAPHIC ORIGIN
China
HISTORY OF INTRODUCTION
Introduced to the United States in 1845.
NORTHEASTERN US DISTRIBUTION
New York, Pennsylvania, Maryland, Virginia
NORTHEASTERN NATIONAL PARKS
REPRODUCTION
Deciduous shrub, flowers in March and April. Reproduces by cuttings or from seeds.
FRUIT AND SEED PRODUCTION
Fruits mature in May and June
CONTROL
SPECIES NAME
Lonicera japonica Thunb.
COMMON NAME
Japanese honeysuckle
FAMILY
Caprifoliaceae
NPS CODE
LONJAP
NPS NORTHEASTERN STATUS
Invasive
THREAT
Forms dense, monotypic thickets, climbing over other vegetation. Spreads, but does not flower or fruit in shade.
INVASIVE ECOLOGY
Tends to be weedy and a rampant grower, can spread or climb 15 to 30 feet, grows as a climbing, twining vine or a groundcover. Easy to grow, tolerant of difficult growing sites, and adaptable to most soils. Outcompetes native plants. Persists in shade, not flowering until canopy is opened.
HABITAT
Moist woodlands, borders of streams, fence rows, disturbed areas, forest edges and mid-successional communities.
GEOGRAPHIC ORIGIN
Eastern Asia
HISTORY OF INTRODUCTION
Introduced to the United States in 1806.
NORTHEASTERN US DISTRIBUTION
Entire Northeast except Vermont
NORTHEASTERN NATIONAL PARKS
BOHA, CACO, DEWA, GATE, MABI, MIMA, SAGA, WEFA
REPRODUCTION
Deciduous shrub, flowers in late April through July. Reproduces by cuttings.
FRUIT AND SEED PRODUCTION
Fruits ripen in August through October.
CONTROL
Prescribed fire, herbicide, mowing, hand-pulling
SPECIES NAME
Lonicera maackii (Rupr.) Herder
COMMON NAME
Amur honeysuckle
FAMILY
Caprifoliaceae
NPS CODE
LONMAA
NPS NORTHEASTERN STATUS
Invasive
THREAT
Produces many seeds and can form dense stands.
INVASIVE ECOLOGY
Shade tolerant, free of pests, easy to grow, adaptable to most soils. Self sows, weedy and can be a rampant grower.
GEOGRAPHIC ORIGIN
Manchuria and Korea
HISTORY OF INTRODUCTION
Introduced 1855-1860
NORTHEASTERN US DISTRIBUTION
Massachusetts, New York, Pennsylvania, New Jersey, Delaware, Maryland, West Virginia, Virginia
NORTHEASTERN NATIONAL PARKS
REPRODUCTION
Deciduous shrub, flowers in May and June. Reproduces by cuttings or by seeds.
FRUIT AND SEED PRODUCTION
Fruits ripen in October and are dispersed by birds and small mammals.
CONTROL
Grubbing, pulling seedlings, cutting, prescribed burning, herbicide
SPECIES NAME
Lonicera morrowii Gray
COMMON NAME
Morrow’s honeysuckle
FAMILY
Caprifoliaceae
NPS CODE
LONMOR
NPS NORTHEASTERN STATUS
Invasive
THREAT
Produces many bird-dispersed fruits and can form dense thickets. This species crosses with Lonicera tatarica and their hybrid gives rise to many taxonomically indistinct offspring.
INVASIVE ECOLOGY
Fast growth rate, easy to grow, produce abundant, many-seeded berries, rapidly invade and overtake an area, compete with native plants for resources such as light, nutrients and pollinators. Seeds remain viable for up to two years in the soil. Possibly secrete allelopathic chemicals into the ground, preventing the growth of other species. Shade tolerant. Grows especially well in calcareous soils.
HABITAT
Near human habitation, wetlands, prairies, forests, stream banks and lake shores.
GEOGRAPHIC ORIGIN
Japan
HISTORY OF INTRODUCTION
Introduced to the United States in 1975.
NORTHEASTERN US DISTRIBUTION
Entire Northeast
NORTHEASTERN NATIONAL PARKS
ACAD, BOHA, CACO, DEWA, MIMA, WEFA
REPRODUCTION
Deciduous shrub, flowers in May. Reproduces by cuttings or seeds.
FRUIT AND SEED PRODUCTION
Fruits ripen in July though September, and are bird dispersed.
CONTROL
Hand pulling, cutting, prescribed burning. European honeysuckle aphid recently introduced to control reproduction.
SPECIES NAME
Lonicera standishii Jacques
COMMON NAME
Standish honeysuckle
FAMILY
Caprifoliaceae
NPS CODE
LONSTA
NPS NORTHEASTERN STATUS
Invasive
THREAT
Can form dense thickets.
INVASIVE ECOLOGY
Forms thickets and shrub layers that crowd and shade out native plants. Decreases light, depletes soil of moisture and nutrients. Competes with natives for pollinators. Grows vigorously and has the ability to invade rapidly.
GEOGRAPHIC ORIGIN
Asia and western Europe
HISTORY OF INTRODUCTION
Probably introduced to the United States as an ornamental.
NORTHEASTERN US DISTRIBUTION
Entire Northeast
NORTHEASTERN NATIONAL PARKS
REPRODUCTION
Semi-evergreen shrub, flowers in April.
FRUIT AND SEED PRODUCTION
Fruits mature in May and June and are dispersed by birds.
CONTROL
Hand pulling of seedlings, cutting, herbicide and prescribed fire.
SPECIES NAME
Lonicera tatarica L.
COMMON NAME
Tatarian honeysuckle
FAMILY
Caprifoliaceae
NPS CODE
LONTAR
NPS NORTHEASTERN STATUS
Invasive
THREAT
Can form, along with its hybrid offspring, dense thickets.
INVASIVE ECOLOGY
Easy to grow and adaptable to most soils. Weedy, tends to self sow. Withstands flooding, drought, shade and temperature extremes. Invades rapidly, creates a dense shrub layer which crowds and shades native plants. Depletes soil of moisture and nutrients and competes with natives for pollinators. Crosses with Lonicera morrowii to form Lonicera X bella.
GEOGRAPHIC ORIGIN
Central Asia to southern Russia
HISTORY OF INTRODUCTION
Introduced to the United States in 1752 as an ornamental, and for shelterbelts, erosion control, wildlife food and cover.
NORTHEASTERN US DISTRIBUTION
Entire Northeast
NORTHEASTERN NATIONAL PARKS
CACO, BOHA
REPRODUCTION
Shrub, flowers late April through June. Reproduces by cuttings or seed.
FRUIT AND SEED PRODUCTION
Fruits mature July through September and are dispersed by birds.
CONTROL
Cutting, pulling, hand-grubbing, herbicide applied to cut stumps, and biocontrol (an aphid species).
SPECIES NAME
Lonicera X bella Zabel (Lonicera tatarica x Lonicera morrowii)
COMMON NAME
Bella honeysuckle
FAMILY
Caprifoliaceae
NPS CODE
LONBEL
NPS NORTHEASTERN STATUS
Invasive
THREAT
Produces many offspring that form dense thickets. This hybrid back-crosses giving rise to many taxonomically indistinct offspring.
INVASIVE ECOLOGY
Capable of rapid invasion, creates a dense shrub layer which crowds and shades native plants. Decreases light and depletes soil of moisture and nutrients. Grows vigorously and competes with native plants for pollinators. Possibly use allelopathic chemical to prevent the growth of other species. Shade tolerant. Grows exceptionally well in calcareous soils.
HABITAT
Near human habitation, wetlands, prairies, forests, stream banks, and lake shores.
GEOGRAPHIC ORIGIN
Asia
HISTORY OF INTRODUCTION
Introduced to the United States in the late 1800s by seeds from Russia.
NORTHEASTERN US DISTRIBUTION
Entire Northeast
NORTHEASTERN NATIONAL PARKS
ACAD, MIMA, SAGA, WEFA
REPRODUCTION
Shrub, flowers in May and June. Reproduces from seed and occasionally vegetatively.
FRUIT AND SEED PRODUCTION
Fruits mature July through September. Dispersed by birds.
CONTROL
Hand pulling of seedlings, cutting, herbicide and prescribed burning. Recently, the European honeysuckle aphid as been introduced to control reproduction.
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