Quercus agrifolia Née

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Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Article from New Trees by John Grimshaw & Ross Bayton

Recommended citation
'Quercus agrifolia' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/quercus/quercus-agrifolia/). Accessed 2024-10-11.

Genus

Quercus
Subgen. Quercus, Sect. Lobatae

Common Names

Encina

Infraspecifics

var. oxyadenia

Other taxa in genus

Glossary

cone: Term used here primarily to indicate the seed-bearing (female) structure of a conifer (‘conifer’ = ‘cone-producer’); otherwise known as a strobilus. A number of flowering plants produce cone-like seed-bearing structures including Betulaceae and Casuarinaceae.
glabrous: Lacking hairs smooth. glabrescent Becoming hairless.

References

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Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Article from New Trees by John Grimshaw & Ross Bayton

Recommended citation
'Quercus agrifolia' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/quercus/quercus-agrifolia/). Accessed 2024-10-11.

Quercus agrifolia in Caspers Wilderness Park, Orange County, California (November 2012). Image John Grimshaw.

An evergreen tree up to 80 ft or more high in California; young shoots densely covered with starry down. Leaves hard in texture, oval or roundish, heart-shaped to tapered at the base, margined with slender, spiny teeth; 1 to 2 in. long, 3⁄4 to 11⁄2 in. wide, dark shining green and glabrous above, paler, not so glossy beneath, and glabrous except for tufts of down in the vein-axils; stalk 1⁄4 to 1⁄2 in. long, stellately downy. Acorns cone-shaped, solitary or in pairs, stalkless, about 1 in. long, 5⁄8 in. wide near the base, tapered gradually to a point, the lower third enclosed in a cup which is silvery within, and covered with close, flattened scales without. They ripen the first year.

Native of California and of Mexico (in Baja California); introduced for the Horticultural Society by Hartweg, in 1849; now very rare. Among cultivated evergreen oaks with spiny toothed leaves it is distinct by reason of the tufts of down in the vein-axils and the tapered, conical acorns. It is an interesting oak, but of no particular merit.

There are several examples of this oak at Kew, which are quite hardy and occasionally bear acorns. The largest is 52 × 53⁄4 ft (1971).

From the Supplement (Vol. V)

specimens: Kew, 54 × 61⁄2 ft (1981); Hillier Arboretum, Ampfield, Hants, pl. 1954, 41 × 31⁄2 ft (1985).

From New Trees

Quercus agrifolia Née

(Subgen. Quercus, Sect. Lobatae)

Coast Live Oak

This species was described by Bean (B460, S406) and Krüssmann (K81).

A plant at Thenford House seen in September 2021, was grown from seed collected at the California Botanic Garden in 2007 as Q. × ganderi but which appears to be Q. agrifolia. Image Maricela Rodriguez.

Nnnew growth on a plant at Arboretum des Pouyouleix, France in August 2021 shows leaves thinly stellate-hairy above when young. Image Béatrice Chassé.

Quercus agrifolia, Arboretum Het Leen, Belgium, September 2009. Image © Jan De Langhe - Arboretum Wespelaar.

Quercus agrifolia seems to be doing better in Spain, Jardín botánico de iturraran, January 2015. Image Paco Garin.

Quercus agrifolia leaves, Silk Wood, Westonbirt, July 2014. Image Charles Snyers.

Quercus agrifolia, flowers, Jardín botánico de Iturraran, Mars 2009. Image Paco Garrin.

Quercus agrifolia, young leaves, Jardín botánico de Iturraran, May 2004. Image Paco Garin.

Quercus agrifolia, young leaves, Jardín botánico de Iturraran, July 2003. Image Paco Garin.

Quercus agrifolia acorns and leaves , Reservoir Road, Stanford, California, October 2018. Image Charles Snyers.

Quercus agrifolia acorns, Pfeiffer Big Sur State Park, CA, February 2008. Image Charles Snyers.

Quercus agrifolia (Jack's Oak), Jack London State Historic Park, Glen Ellen, CA, February 2006. This old oak on the ranch where Jack London resided from 1905 until his death in 1916, was removed in 2013. Image Charles Snyers.

Quercus agrifolia (Jack's Oak), Jack London State Historic Park, Glen Ellen, CA, February 2006. Image Charles Snyers.

Quercus agrifolia, UC Davis Campus, October 2018. Image Charles Snyers.

Quercus agrifolia, Santa Barbara Botanic Garden, CA, October 2018. Image Charles Snyers.

Quercus agrifolia acorns, El Moro Elfin Forest, Los Osos, California, October 2018. Image Charles Snyers.

Quercus agrifolia acorns, Sugarloaf State Park, Sonoma County, CA, October 2018. Image Charles Snyers.

The Belgian climate is not ideal for Quercus agrifolia. This photograph illustrates the leaves of the Belgian champion in the collection of the late Mr. Dumont (4 m high × 22 cm in Cr), taken in July 2018. Image Charles Snyers.

El Moro Elfin Forest, a 90-acre State Park in Los Osos, California, is home to more than 200 different plants, dominated by pygmy coast live oaks, Quercus agrifolia. Image Charles Snyers.

These coast live oaks were once described as Quercus agrifolia var. frutescens because of their shrubby habit. It has since been demonstrated that edaphic factors determined their habit. Image Charles Snyers.

The Ancestor Tree, Quercus agrifolia, Halter Ranch Winery, San Luis Obispo County, CA (28 October 2018). Isolated on top of a hill in the vineyards, It is also clearly visible on Google Maps. Image Charles Snyers.

The Ancestor Tree was 28 m high and 32 m wide and its circumference 823 cm, in October 2018, Halter Ranch Winery. Image Charles Snyers.

The Ancestor Tree, the largest Quercus agrifolia in California (and in the world) at the Halter Ranch Winery, near the city of Paso Robles, San Luis Obispo County, CA (28 October 2018). Image Charles Snyers.

A magnificent Quercus agrifolia in Caspers Wilderness Park, Orange County, California (November 2012). Image John Grimshaw.

It forms part of The National Bonsai & Penjing Museum at the US National Arboretum, Washington. April 2018. Image © Koen Camelbeke, Arboretum Wespelaar.

var. oxyadenia (Torr.) J.T. Howell

This variety differs from typical Q. agrifolia in that persistent stellate pubescence forms a felt-like covering on the branchlets, petioles and lower leaf surfaces. Var. agrifolia is entirely glabrous. Howell 1931. Distribution MEXICO: Baja California; USA: southern California. Habitat High valleys and canyon floors at about 1400 m asl. USDA Hardiness Zone 8. Conservation status Least Concern. Illustration NT698. Taxonomic note Valencia-A. (2004) does not distinguish var. oxyadenia.

This taxon was introduced to the United Kingdom by Warner and Howick (WAHO 345) from a collection made in San Diego Co., California in 1986. At Kew a specimen from this gathering has made a fine tree of c.10 m, with numerous vertical branches, forming a dense canopy that extends to the ground. This was fruiting freely in November 2005.