Short description of Epilobium brunnescens, New Zealand Willowherb

New Zealand willowherb is a prostrate, mat-forming plant with most leaves opposite, becoming reddish in sunlight. The flowers are held erect or drooping, well above the plant.

Impact summary: Epilobium brunnescens, New Zealand Willowherb

The actual impact of New Zealand willowherb is difficult to assess; it certainly occupies large areas of the beds of standing and flowing water bodies which might otherwise support native plants.

Habitat summary: Epilobium brunnescens, New Zealand Willowherb

In New Zealand it grows on stream beds, flushes, disturbed river gravel and other open, moist rocky places, in areas of high rainfall. In GB it typically grows on damp, otherwise bare ground, particularly river gravels and disturbed ground.

Overview table

Environment	Terrestrial
Species status	Non-Native
Native range	Australia, New Zealand
Functional type	Land plant
Status in England	Non-Native
Status in Scotland	Non-Native
Status in Wales	Non-Native
Location of first record	v.c.83
Date of first record	1904

Origin

New Zealand willowherb is native throughout New Zealand, apart from the east coast of North Island and on Macquarie Is in Australia; subsp. beaugleholei occurs in Victoria State.

First Record

New Zealand willowherb was first recorded in GB in Edinburgh in 1904 or 1908, according to different sources.

Pathway and Method

New Zealand willowherb was first brought into GB for horticulture and presumably escaped by wind-dispersed seed.

Species Status

New Zealand willowherb is native to New Zealand and is established but not invasive in Norway and Sweden. In GB, from its first record in 1904, at least until 1986, it had been recorded from fewer than 150 10km squares. However, in 2000 it was reported from nearly 1400 10km squares and is currently known from more than 2000 10km squares.

Dispersal Mechanisms

The wind dispersal capacity of seed is amongst the most effective of any plant and is more than sufficient to explain the dispersal of this species in GB.

Reproduction

Reproduction is mainly by seed, although it is also capable of rooting from the nodes of fragments of stem.

Known Predators/Herbivores

None known.

Resistant Stages

None known.

Habitat Occupied in GB

E. brunnescens typically grows on damp, otherwise bare ground, particularly river gravels and disturbed ground associated with railways, woodland and tracks.

New Zealand willowherb is now widespread and abundant throughout upland and western oceanic areas of GB, with a few scattered populations outside these areas.

Environmental Impact

Has so far been considered to be a benign member of the upland flora. However, in recent years, it has increasingly been noted growing in dense and largish patches in upland calcareous grassland, almost swamping the native plants in this habitat.

Health and Social Impact

None known.

Economic Impact

None known.

Identification

Stace, C.A. (2010) New flora of the British Isles, Third Edition, Cambridge University Press, Cambridge.

Sell, P.D. & Murrell, G. (2009) Flora of Great Britain and Ireland. Volume 3: Mimosaceae - Lentibulariaceae, Cambridge University Press, Cambridge, UK.

Biology, ecology, spread, vectors

None known.

Management and impact

None known.

General

Stace, C.A. (2010) New flora of the British Isles, Third Edition, Cambridge University Press, Cambridge.