Quercus robur
English oak, pedunculate oak, Pedunculate Oak
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Family: Fagaceae · Type: Tree · Not Native
Quercus robur (English oak) is a non-native California tree in the Fagaceae family, recognized by only deciduous oak with deeply lobed leaves and 1-year acorn maturation.
English oak is a naturalized tree found in the southern Santa Cruz Mountains along roadsides, pastures, and forest margins at elevations below 1,000 meters. Flowering from March to April, this deciduous tree produces small, unremarkable flowers typical of oak species. Growing to heights of 30 meters with a light gray, scaly trunk, it develops a spreading canopy characteristic of mature oaks. Its leaves are large, 5 to 15 centimeters long, with deep, rounded lobes and a strongly cordate base, displaying a rich deep to light green color with a shiny surface. The tree produces distinctive acorns in hemispherical cups 13 to 20 millimeters wide, which mature within a single year.
Identification and appearance
Key characters: 19 sympatric species; only deciduous oak with deeply lobed leaves and 1-year acorn maturation
Habitat and range
Habitat: Roadsides, pastures, forest margins, woodlands, persisting near old homesites
Elevation: < 1000 m
Outside California: Washington, British Columbia to Prince Edward Island, native to Europe
Bloom period
Quercus robur blooms Mar-Apr.
How to tell it apart
vs Prunus: Quercus has acorns in cups; cherries/plums have fleshy round fruits.; vs Notholithocarpus: Quercus has drooping catkins; tanoak has upright flower spikes.; vs Rhamnus: Quercus has acorns; buckthorns have berry-like fruits.; vs Ceanothus: Quercus has acorns; California lilacs have small capsule fruits.; vs Platanus: Quercus has acorns; sycamores have hanging ball-shaped seed clusters.
Frequently asked questions
Is Quercus robur native to California?
No. Quercus robur is not native to California (recorded as not native).
When does Quercus robur bloom?
Quercus robur blooms Mar-Apr.
What plant family does Quercus robur belong to?
Quercus robur is in the Fagaceae family, genus Quercus.
What habitat does Quercus robur grow in?
Quercus robur grows in Roadsides, pastures, forest margins, woodlands, persisting near old homesites.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.