Mid-Atlantic Invaders Tool

Description

Appearance

Epilobium hirsutum is a semi-aquatic perennial herbaceous plant. The plant is erect, branching, covered with soft hairs and grows up to 6 ft. (1.8 m) tall. E. hirsutum is native to Africa, temperate Asia and Europe.

Foliage

E. hirsutum leaves are opposite, sessile and clasp the stem. Leaf blades are lanceolate-elliptic to narrowly obovate or elliptic 1.6-4.7 in. (4-12 cm) long and 0.12-1.6 in. (0.3-4 cm) wide. Foliage is villous both above and below with a serrulate margin. Leaf tip is acute to acuminate.

Flowers

Solitary flowers are held on stems arising from the upper leaf axils. Stems can be floating or lying on the ground. The flowers are showy with bright pink to dark purple notched petals with white centers.

Fruit

E. hirsutum reproduces by seeds, rhizomes and stolons. Fruits are narrow, pubescent, dehiscent seed pods from 1-3.5 in. (2.5-9 cm) long that contain numerous seeds. Seeds have long white hairs that aid in dispersal by wind.

Ecological Threat

E. hirsutum is an extremely widespread and variable species that spreads aggressively by vegetative growth in sunny open wetland habitats, although it can also invade uplands. It can form monocultures in natural wetlands, crowding out native species.

Uses

Landscape Ornamental Use (GRIN): No

All Uses (GRIN):

Distribution Map (EDDMapS)

Wetland Indicator

Summary: hairy willowherb (Epilobium hirsutum) is a Wetland species.

Atlantic and Gulf Coastal Plain (AGCP):

Mid-Atlantic Coastal Plain regions

Eastern Mountains and Piedmont (EMP):

Mid-Atlantic Piedmont and Mountain regions

Northcentral and Northeast (NCNE):

Northern parts of PA and NJ (and beyond)

Legend (data from U.S. Army Corps of Engineers)

OBL (Obligate wetland): Almost always occurs in wetlands (estimated probability > 99%) under natural conditions

FACW (Facultative wetland): Usually occurs in wetlands (estimated probability 67% - 99%), but occasionally found in non-wetlands

FAC (Facultative): Equally likely to occur in wetlands (estimated probability 34% - 66%) or non-wetlands

FACU (Facultative upland): Usually occur in non-wetlands (estimated probability 67% - 99%), but occasionally found in wetlands (estimated probability 1% - 33%)

UPL (Obligate upland): Occur almost always (estimated probability > 99%) in non-wetlands under natural conditions

Taxonomic Rank