Quercus ilex
Holly oak
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Family: Fagaceae · Type: Tree · Not Native
Quercus ilex (Holly oak) is a non-native California tree in the Fagaceae family, recognized by non-native status and distinctive woolly leaf undersides.
Holly oak is a naturalized tree found in southwestern California on canyon slopes and washes near developments at elevations of 50 to 400 meters. Flowering from May to August, this evergreen produces small greenish flowers in subtle clusters. Growing to 20 meters tall with a distinctive gray-black trunk that breaks into small plates and dense gray-brown woolly branches, the tree has a robust, spreading form. Its leathery leaves are lanceolate to ovate, 3 to 8 centimeters long, with a glossy dark green upper surface and a woolly yellowish-white underside, featuring margins that are entire or lightly spine-toothed. The acorn cup is thin and top-shaped, 7 to 15 millimeters wide, containing an ovoid nut 15 to 25 millimeters long.
Identification and appearance
Key characters: 26 sympatric species; non-native status and distinctive woolly leaf undersides
Habitat and range
Habitat: Escaped from cultivation, canyon slopes, washes near developments
Elevation: 50-400 m
California counties: Ventura, Los Angeles, Riverside, San Diego, Orange, Solano, Butte, Contra Costa, Sacramento, Yolo, Santa Clara
Outside California: native to Mediterranean
Bloom period
Quercus ilex blooms May-Aug.
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 ilex native to California?
No. Quercus ilex is not native to California (recorded as not native).
When does Quercus ilex bloom?
Quercus ilex blooms May-Aug.
Where in California does Quercus ilex grow?
Quercus ilex occurs in Ventura, Los Angeles, Riverside, San Diego, Orange, Solano, Butte, Contra Costa and other counties, at elevations of 50-400 m.
What plant family does Quercus ilex belong to?
Quercus ilex is in the Fagaceae family, genus Quercus.
What habitat does Quercus ilex grow in?
Quercus ilex grows in Escaped from cultivation, canyon slopes, washes near developments.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · 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.