Island Oak, Quercus tomentella

About Island Oak (Quercus tomentella) 20 Nurseries Carry This Plant

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The Island Oak (Quercus tomentella), also known as Island Live Oak or Channel Islands Oak, is an oak in the section Protobalanus. It is a rare species, included on CNPS list 4.2 due to limited distribution in the wild. Fossil evidence shows that this species was once widespread on the mainland. Island Oak is endemic to six islands off the coast of California, Santa Rosa, Santa Cruz, Anacapa, Santa Catalina, San Clemente, and Guadalupe islands. The first five islands are Channel Islands of California; Guadalupe Island is located to the west of Baja California, Mexico. Island Oak is a tree usually less than 20 meters in height. Its bark is usually gray and becomes furrowed with age. The specific name tomentella, Latin for "beset with tomentum (fuzz)", references the dense hairs found on the undersides of its leaves. Leaves, which are evergreen, are usually 5-8 centimeter in length, oblong to oblong-obvate in shape, with a toothed margin, deeply indented. Acorns take 2 years to mature and are saucer- to bowl-shaped with a rounded tip, and large in size (cup 20-30 millimeter wide, 6-8 millimeter deep, nut 20-35 millimeter).

In the garden it is fast growing and trouble-free. It is best used near the coast, but can tolerate inland conditions within about 20 miles of the coast if given some protection and a little extra water during dry times, especially when the young plant is getting established.

Plant Description

Plant Type

Tree

Size

33 - 66 ft tall
35 ft wide

Form

Rounded, Upright Columnar

Growth Rate

Fast, Moderate

Dormancy

Evergreen

Flower Color

Cream, Green

Flowering Season

Spring, Summer

Wildlife Supported

Many insects, birds, reptiles and mammals are attracted to oaks. Many insects are attracted to Oaks generally, including the following butterflies which use Oaks as host plant: California Sister, Propertius Duskywing, Mournful Duskywing, Golden Hairstreak, and Gold-Hunter's Hairstreak.
Bird gardens

Butterflies & moths hosted ( 1 confirmed

, 31 likely * ) SHOW ALL

Chionodes trichostolaChionodes trichostola

California Sister Adelpha californicaAdelpha californica

Mournful Duskywing Erynnis tristisErynnis tristis

White-lined Sphinx Hyles lineataHyles lineata

Western Tussock Moth Orgyia vetustaOrgyia vetusta

California Oak Moth Phryganidia californicaPhryganidia californica

Oak Winter Highflier Moth Hydriomena nubilofasciataHydriomena nubilofasciata

Landscaping Information

Sun

Full Sun, Part Shade

Moisture

Low

Summer Irrigation

Max 2x / month once established

Nurseries

Carried by 20

Ease of Care

Moderately Easy

Cold Tolerance

Tolerates cold to 15° F

Soil Drainage

Medium

Soil Description

Tolerates a wide variety of soils, including very rocky conditions. Soil PH: 6.0 - 7.2

Common uses

Bank Stabilization, Hedges, Bird Gardens, Butterfly Gardens

Companion Plants

Due to its relative large leaves and dense foliage, it often has no understory. However, it can be used adjacent to many other island plants such as Santa Cruz Island Ironwood (Lyonothamnus floribundus ssp. asplenifolius), Catalina Cherry (Prunus ilicifolia ssp. lyonii), Island Bristleweed (Hazardia detonsa), Redflower Buckwheat (Eriogonum grande var. rubescens), Island Snapdragon (Gambelia speciosa), and Giant Coreopsis (Leptosyne gigantea). Other chaparral and sage scrub companions include California Encelia (Encelia californica), California Sagebrush (Artemisia californica), Bladderpod (Peritoma arborea), and Ceanothus spp

Propagation?

For propagating by seed: Fresh seeds sow in fall outdoors or stratify to hold for spring sowing. (USDA Forest Service 1974).

Sunset Zones?

5, 7, 8, 9, 14*, 15*, 16*, 17*, 19*, 20*, 21*, 22*, 23*, 24*

Natural Setting

Site Type

Slopes, bluffs and canyons of the Channel Islands where fog is frequent

Climate

Annual Precipitation: 7.8" - 19.5", Summer Precipitation: 0.14" - 0.40", Coldest Month: 45.6" - 57.6", Hottest Month: 62.9" - 73.3", Humidity: 1.50" - 16.69", Elevation: -2006" - 2362"

Alternative Names

Common Names: Island Live Oak

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Sources include: Wikipedia. All text shown in the "About" section of these pages is available under the Creative Commons Attribution-ShareAlike License. Plant observation data provided by the participants of the California Consortia of Herbaria, Sunset information provided by Jepson Flora Project. Propogation from seed information provided by the Santa Barbara Botanical Garden from "Seed Propagation of Native California Plants" by Dara E. Emery. Sources of plant photos include CalPhotos, Wikimedia Commons, and independent plant photographers who have agreed to share their images with Calscape. Other general sources of information include Calflora, CNPS Manual of Vegetation Online, Jepson Flora Project, Las Pilitas, Theodore Payne, Tree of Life, The Xerces Society, and information provided by CNPS volunteer editors, with special thanks to Don Rideout. Climate data used in creation of plant range maps is from PRISM Climate Group, Oregon State University, using 30 year (1981-2010) annual "normals" at an 800 meter spatial resolution.

Links: Jepson eFlora Taxon Page CalPhotos Wikipedia Calflora

Island Oak

Quercus tomentella

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Island OakQuercus tomentella

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Island Oak

Quercus tomentella