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Quercus robur, the pedunculate (or "English") oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native plant to most of Europe and western Asia, and is widely cultivated in other temperate regions. It grows on soils of near neutral Soil pH in the lowlands and is notable for its value to natural ecosystems, supporting a very wide diversity of herbivorous insects and other pests, predators and pathogens.
The crown is spreading and unevenly domed, and trees often have massive lower branches. The bark is greyish-brown and closely grooved, with vertical plates. There are often large burrs on the trunk, which typically produce many small shoots. Oaks do not produce Basal shoot but do recover well from pruning or lightning damage. The twigs are hairless and the buds are rounded (ovoid), brownish and pointed. (1974). 9780002192132, Collins. ISBN 9780002192132 (2026). 9780723251750, Frederick Warne. ISBN 9780723251750
The leaves are arranged alternately along the twigs and are broadly oblong or ovate, 10–12 cm long by 7–8 cm wide, with a short (typically 2–3 mm) petiole. They have a cordate (auricled) base and 3–6 rounded lobes, divided no further than halfway to the midrib. The leaves are usually glabrous or have just a few simple hairs on the lower surface. They are dark green above, paler below, and are often covered in small disks of spangle gall by autumn.
Flowering takes place in spring (early May in Northern Europe) and the flowers are wind-pollinated. The male flowers occur in narrow catkins some 2-4 cm long and arranged in small bunches. The female flowers are small, brown with dark red stigmas, about 2 mm in diameter and are found at the tips of new shoots on peduncles 2–5 cm long.
The fruits () are borne in clusters of 2–3 on a long peduncle (stalk) 4–8 cm long. Each acorn is 1.5–4 cm long, ovoid with a pointed tip, starting whitish-green and becoming brown, then black. As with all oaks, the acorns are carried in a distinctive shallow cup which can be useful in identifying the species. It is an "alternate bearing" species, with large crops produced every other year. (2026). 9780954334741, Brambleby Books. ISBN 9780954334741
Quercus cerris is also sometimes confused with it, but that species has "whiskers" on the winter buds and deeper lobes on the leaves (often more than halfway to the midrib). The acorn cups are also very different.
The genome of Q. robur has been completely sequenced (GenOak project); the first version was published in 2016. It comprises 12 chromosome pairs (2 n = 24), about genes and 750 million base pair.
There are many synonyms, and numerous varieties and subspecies have been named. The populations in Iberia, Italy, southeast Europe, and Asia Minor and the Caucasus are sometimes treated as separate species, Q. orocantabrica, Q. brutia Tenore, Q. pedunculiflora K. Koch and Q. haas Kotschy respectively.
Quercus × rosacea Bechst. (Sessile oak x Q. robur) is the only naturally occurring hybrid, (2026). 9780901158482, Botanical Society of Britain and Ireland. ISBN 9780901158482 but the following crosses with other white oak species have been produced in cultivation:
There are numerous cultivars available, among which the following are commonly grown:
Its Indicator value (as revised in 2022) in Europe are L = 7, T = 6, F = 6, R = 5, N = 2-6 and S = 0, which describe how it favours conditions of bright sunlight, moderate temperature, moisture and pH, a wide range of nutrient levels, and low salinity.
In 2019 it was estimated that 2,300 species of insect, bryophyte, lichen, bird, mammal or other species are associated with Q. robur in the UK. Some entirely rely on it while other can make use of other tree species. Within its native range, Q. robur is valued for its importance to and other wildlife, famously supporting the highest biodiversity of insect herbivores of any British plant (at least 400 species). The most well-known of these are the ones that form galls, which number about 35. The knopper gall is very common, and Andricus grossulariae produces somewhat similar spiky galls on the acorn cups. Also common are two types of spherical galls on the twigs: the Andricus kollari and the cola nut gall. The latter are smaller and rougher than the former. A single, large exit hole indicates that the wasp inside has escaped, whereas several smaller holes show that it was parasitised by another insect, and these emerged instead. The undersides of oak leaves are often covered in spangle galls, which persist after the leaves fall.
One of the most distinctive galls is the oak apple, a 4.5 cm diameter spongy ball created from the buds by the wasp Biorhiza pallida. The pineapple gall, while less common, is also easily recognised.
The quantity of caterpillar species on an oak tree increases with the age of the tree, with blue tits and timing their egg hatching to the leaves opening. (2026). 9781784272197, Pelagic. ISBN 9781784272197 The most common caterpillar species include the winter moth, the Tortrix viridana and the mottled umber, all of which can become extremely abundant on the first flush of leaves in May, but the oak trees do recover their foliage later in the year.
The acorns are typically produced in large quantities every other year (unlike Q. petraea, which produces large crops only every 4-10 years) and form a valuable food resource for several small and some birds, notably Garrulus glandarius. Jays were overwhelmingly the primary propagators of oaks before humans began planting them commercially (and remain the principal propagators for wild oaks), because of their habit of taking acorns from the umbra of its parent tree and burying them undamaged elsewhere.
Additionally, although bitter due to their high tannin content, the acorns can be roasted and ground into a coffee substitute.
In 1746, all oak trees in Finland were legally classified as royal property, and oaks had enjoyed legal protection already from the 17th century. The oak is also the regional tree of the Southwest Finland region.
During the French Revolution, oaks were often planted as trees of freedom. One such tree, planted during the 1848 Revolution, survived the destruction of Oradour-sur-Glane by the Nazis. After the announcement of General Charles de Gaulle's death, caricaturist Jacques Faizant represented him as a fallen oak.
In Germany, the oak tree can be found in several paintings of Caspar David Friedrich and in "Of the life of a Good-For-Nothing" written by Joseph Freiherr von Eichendorff as a symbol of the state protecting every citizen.
In Serbia the oak is a national symbol, having been part of the historical coat of arms of the Socialist Republic of Serbia, the historical coat of arms and flags of the Principality of Serbia, as well as the current traditional coat of arms and flag of Vojvodina.
In England, the oak has assumed the status of a national emblem. This has its origins in the oak tree at Boscobel House, where the future King Charles II hid from his Roundhead pursuers in 1650 during the English Civil War; the tree has since been known as the Royal Oak. This event was celebrated nationally on 29 May as Oak Apple Day, which continues to this day in some communities.
Many place names in England include a reference to this tree, including Oakley, Occold and Eyke. Copdock, in Suffolk, probably derives from a pollarded oak ("copped oak"). (2026). 9780956458407, D.K. & M.N. Sanford. ISBN 9780956458407 'The Royal Oak' is the third most popular pub name in Britain (with 541 counted in 2007) and HMS Royal Oak has been the name of eight major Royal Navy warships. The naval associations are strengthened by the fact that oak was the main construction material for sailing warships. The Royal Navy was often described as "The Wooden Walls of Old England" (a paraphrase of the Delphic Oracle) and the Navy's official quick march is "Heart of Oak". In folklore, the Major Oak is where Robin Hood is purported to have taken shelter.
Oak leaves (not necessarily of this species) have been depicted on the Croatian 5 Croatian kuna coin; on old German Deutsche Mark currency (1 through 10 Pfennigs; the 50 Pfennigs coin showed a woman planting an oak seedling), and now on German-issued euro currency coins (1 through 5 cents); and on British pound coins (1987 and 1992 issues).
In Northern Ireland, the city of Derry, and the county of Londonderry, is an anglicisation of the Irish Daire or Doire, which translates as 'oak-grove/oak-wood'.
Two individuals of notable longevity are the Stelmužė Oak in Lithuania and the Granit Oak in Bulgaria, which are believed to be more than 1500 years old, possibly making them the oldest oaks in Europe; another specimen, called the 'Kongeegen' ('Kings Oak'), estimated to be about 1,200 years old, grows in Jaegerspris, Denmark. Yet another can be found in Rumskulla oak, Sweden, that is over 1000 years old and around. Of maiden (not pollarded) specimens, one of the oldest is the great oak of Ivenack, Germany. Dendrochronology of this tree and other oaks nearby gives an estimated age of 700 to 800 years. Also the Bowthorpe Oak in Lincolnshire, England is estimated to be 1,000 years old, making it the oldest in the UK, although there is Knightwood Oak in the New Forest that is also said to be as old. The highest density of Q. robur with a circumference of and more is in Latvia. (2026). 9789984827155, Lauku Avīze. ISBN 9789984827155
In Ireland, at Birr Castle, a specimen over 400 years old has a girth of , known as the Carroll Oak.Fifty Trees of Distinction by Prof. D.A. Webb and the Earl of Ross. Booklet, published by Birr Castle Demesne, 2000.
In the Basque Country (Spain and France), the 'Gernikako Arbola' is an ancient oak tree located in Gernika, under which the Lehendakari (Basque prime minister) swears his oath of office.
The largest example in Australia is in Donnybrook, Western Australia.
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