Northern Ireland's Priority Species

Calamagrostis epigejos – wood small-reed


Distribution map

Click here to view an interactive map of the Northern Ireland dataset as currently collated by CEDaR.
The map is generated through the NBN Gateway using their Interactive Mapping Tool.


Calamagrostis epigejos (L.) Roth
Family: Poaceae

Although frequent and even invasive in much of its geographical range, this grass has only ever been recorded as a native in two locations in Northern Ireland, and is presumed extinct in one of them.

In brief

  • A distinctive, tall reed-like grass
  • Found in a single location (County Londonderry, in Northern Ireland) below oak woodland
  • Widely distributed in Eurasia where it is common in a wide variety of habitats
  • Most impressive in June and July when it flowers
  • It is rare and has declined. It is also an Irish Red Data Book species
  • The loss of this species from its only other recorded site in Northern Ireland has been attributed to afforestation.

Species description
This is one of our tallest grasses, the flowers, borne above dense tussocks of arching leaves, can attain a height of 200cm. The leaves are flat, up to 12mm wide, ribbed on the upper surface, coarse and rough to the touch. The narrow feathery flower head, or panicle, is light green, often flushed with purple and up to 30cm long, comprising hundreds of individual flowers, each enclosed by two very narrow pointed scales 5-7mm long which eventually gape to reveal the reproductive parts amongst a mass of fine white hairs arising from the base of less conspicuous narrow inner scales.

Life cycle
This perennial grass has creeping rhizomes with which it may spread vegetatively. Flower heads form in July and August — genetic inbreeding is not possible as the flowers are self incompatible, so genetic diversity is high — this is an adaptable plant. Seeds are immediately viable and do not require a period of dormancy.

Similar species
In the UK mainland there is possible confusion with purple small-reed (Calamagrostis canescens) but this is not a species that has been recorded anywhere in Ireland. Here, it can be distinguished from other reed-like species by its ligule — a membrane that may extend up the stem at the junction of the leaf and stem, which in this species is long and narrow, unlike any of the more common reed-like species.

How to see this species
In Northern Ireland it is currently known from a single location — Craigall Rocks, south-east of Moneydig in Coleraine, found by John Harron in 1987. It is tolerant of a wide range of light conditions, soil wetness and soil nutrient conditions and is known as a species that can inhabit a notably wide range of different habitats, from dunes to fens to woodlands to open man-made habitats. It is most impressive in June and July when it flowers. Relevant access permissions should always be sought prior to visiting any sites.

Current status
Located by Dr David Moore at Fermoyle Hill, Drumboe, County Londonderry in the early nineteenth century, but not seen there since 1937, leaving the Craigall Rocks site presumed to be its only extant Northern Irish location where its current status is unknown, but there is no reason why it should not have maintained its presence.

It occurs across the Eurasian continent, is very common in central Europe, is common in parts of central and southern England, scattered throughout the British mainland. It occurs as a problematic invasive alien weed in parts of North America, but it remains very rare in Ireland.

Why this adaptable species fails to prosper in Northern Ireland is a matter for speculation. In Europe it is invasive in metalliferous spoil from mining, yet it is not considered to have metal tolerance in the ecological flora of the British Isles’ account of ecological characteristics. It could be that we have a different genotype here.

Why is this species a priority in Northern Ireland?

  • It is rare and has undergone a decline.

It does not meet Red Data Book criteria in the UK (it is a species of ‘least concern’), but is included as ‘Rare’ in the Irish RDB of 1987 and provisionally as ‘Vulnerable’ in the forthcoming revision.

Threats/Causes of decline
The loss of this species from its only other recorded site in Northern Ireland has been attributed to afforestation.

Conservation of this species

Current action

  • Craigall Rocks, Culnaman and Grove River Wood has been identified as a Site of Local Nature Conservation Importance and is additionally an Area of Constraint on Mineral Development under the Northern Area Local Plan.

Proposed objectives/actions

  • The status of wood small-reed will be surveyed and monitored and appropriate conservation action undertaken if required.

What you can do
If you refind the colony at Craigall Rocks, or identify this species in any other location, make a note of the approximate dimensions of the stand(s) and submit this information to the Department of Botany, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU or to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU. Tel. 028 9039 5256. The information will be passed to Environment and Heritage Service.

Further information

Flora of Northern Ireland

Rebele, F. and Lehmann, C. (2001). Biological Flora of Central Europe: Calamagrostis epigejos (L.) Roth. Flora 196(5): 325-344.

Text written by:
Shaun Wolfe-Murphy