Quercus rubra | Red Oak | Dair Dearg



Conservation status

Not Assessed


Invasive species - risk of Medium Impact

Irish status

Occasionally present, casual, vagrant, migratory

Introduction pathways - 1

Escape from Confinement

Introduction pathways subclass - 1

Ornamental purpose

Invasive score


NAPRA Ireland risk assessed


Species Biology


Fast growing deciduous oak tree, up to 30m tall with a diameter of 1.8m, large leaves 20-25cm long with 4-6 irregularly toothed lobes (Booy et al., 2015). Acorn cup is extremely shallow, covering less than one third of the acorn with oval scales (Booy et al., 2015).


Outcompetes and displaces native vegetation (Booy et al., 2015; Preston et al., 2004), as well as potentially being a vector for the further spread of Phytophthora ramorum (Sudden Oak death).


Woodland, forest and other wooded land; Regularly or recently cultivated agricultural, horticultural or domestic habitat Constructed, industrial or other artificial habitats,

Pathway and vector description

Cultivated in Britain since 1720s at least (Preston et al., 2004), it is likely to have been planted in Ireland in the 18th century and is still widely available in garden centres and nurseries. The "King Oak" in Tullamore, considered one of the oldest trees in Ireland, is a red oak.

Mechanism of impact


Broad environment


Habitat description

Planted in gardens and parks but also found in natural and semi natural woodlands (Preston et al., 2004).

Species group


Native region

North America

Similar species

Quercus cerris


World distribution(GBIF)

Irish distribution

Established - Widespread but localised.

Native distribution

Native to eastern North America (Preston et al., 2004).

Temporal change

Date of first record category


Fifty year date category


Records submitted to Data Centre in 2021

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How can you help

Report any sightings to the National Biodiversity Data Centre.



Preston, C.D., Pearman, D. A. & Dines, T. D. (2002). New atlas of the British and Irish flora. An atlas of the vascular plants of Britain, Ireland, the Isle of Man and the Channel Islands, Oxford University Press. Booy, O., Wade, M. & Roy, H. (2015) A Field Guide to Invasive Plants & Animals in Britain. Bloomsbury.