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Plant type

Tree

Size

16 - 82 ft Tall
30 ft Wide

Form

Upright, Rounded, Upright Columnar

Growth rate

Slow

Dormancy

Summer Semi-deciduous, Winter Deciduous

Fragrance

None

Color

Yellow, Cream, Green

Flowering season

Spring, Winter

Common uses

Bank stabilization, Deer resistant

The majestic blue oak is a drought-tolerant deciduous tree that provides food and shelter for local wildlife. It supports birds, squirrels and insects. It is a host plant for several species of butterflies and moths.

This tree gets its name from its blue-green leaves. The bark is pale gray and textured. Blue oaks are slow-growing, but can grow to 80+ feet in height. The canopy can spread to a width of 30 feet or more. It requires a good-sized planting area and does best on dry, well-drained slopes.

Sun

Full Sun, Partial Shade

Water

Low, Very Low

Summer irrigation

Max 1x / month once established

Ease of care

Easy

Cold tolerance

Tolerates cold to 0° F

Soil drainage

Fast

Soil description

Tolerant of a variety of soils as long as adequate drainage is provided.
Soil PH: 6.0 - 8.0

Maintenance

Young trees should be pruned for desired shape

Propagation

From acorns, although hybridization is common.For propagating by seed: Fresh seeds sow in fall outdoors or stratify to hold for spring sowing. If started indoors or in glasshouse, stratify first for 1.5 mos. (USDA Forest Service 1974).

Sunset Zones

1, 2, 3, 4, 5, 6, 7*, 8, 9*, 10, 11, 14*, 15*, 16*, 17, 18*, 19*, 20*, 21*, 22, 23, 24

Coffeeberry (Rhamnus spp.), Buckbrush (Ceanothus cuneatus), Chaparral Whitethorn (Ceanothus leucodermis), Big Berry Manzanita (Arctostaphylos glauca), Buckeye (Aesculus californica), Mountain Mahogany (Cercocarpus betuloides), other oaks (Quercus spp.), pines (Pinus spp.), and native grasses.

California Buckeye

Aesculus californica

Big Berry Manzanita

Arctostaphylos glauca

Buck Brush

Ceanothus cuneatus

Chaparral Whitethorn

Ceanothus leucodermis

Birds
Caterpillars
Pollinators

Butterflies and moths supported

11 confirmed and 159 likely

Confirmed Likely

Abagrotis baueri

Sallow Button

Acleris hastiana

Acrobasis caliginella

Acrobasis comptella

Site type

Rocky, hot, dry hillsides and slopes usually below 3, 500 ft. in the Coast Ranges and foothills of the Sierra, often in large stands of Blue Oak Woodland or Blue Oak Savannah.

Plant communities

Chaparral, Foothill Woodland, Oak Woodland, Woodland