Bear Oak
Quercus ilicifolia
Fagaceae · broadleaf deciduous tree · introduced
Last updated
Plant Profile
Size & Form
Height
25 ft
Spread
40-70 ft
Site Requirements
Light
Full Sun
Soil Drainage
Adaptable
Soil pH
4.5-8.5 (strongly acidic to strongly alkaline)
Water
Moderate
Drought Tolerance
Moderate
Hardiness
Zones 5a–8b
Ornamental Interest
Bloom Time
Winter, Spring
Origin
northeastern U
Watch for this season
Cytospora CankerHigh
Peak Spore Production and Dispersal
Powdery MildewHigh
Active Conidial Spread
Anthracnose (Shade Trees)Moderate
Active Infection & Secondary Spread
Armillaria Root RotModerate
Active Below-ground Growth
+ 3 more — see full disease and pest lists below
Diseases: Regionally Documented (13)
Ramorum Blight (Sudden Oak Death) Mistletoe Armillaria spp. — primarily A Armillaria Root Rot Discula destructiva (dogwood), Kabatiella and Discula spp... Anthracnose Cytospora spp. (Valsa spp., Leucostoma spp.) Cytospora Canker Microstroma album Frosty Mildew Ganoderma applanatum Ganoderma Root and Butt Rot Pseudoinonotus dryadeus Inonotus Root and Butt Rot Taphrina spp. Leaf Blister Phoradendron villosum Mistletoe (a True Mistletoe) Neonectria ditissima Nectria Canker Multiple obligate biotrophic fungi (Erysiphales: Erysipha... Powdery Mildew Inonotus dryophilus White Pocket Rot (Piped Rot)
Pests: Regionally Documented (14)
Looper Stem Gall Asterolecanium spp. Pit scale Platycotis vittata Oak Treehoppers Bucculatrix albertiella Oak Ribbed Casemaker Phylloxera spp. Oak leaf phylloxera Various (Cynipidae, Cecidomyiidae, Eriophyidae, Psyllidae) Leaf galls Neuroterus saltatorius Jumping Oak Gall Andricus quercuscalifornicus California Gallfly Prionoxystus robiniae Carpenterworm Oak gall wasp Bucculatrix ainsliella Oak skeletonizer Edwardsiana rosae Rose leafhopper Various (Cynipidae, Cecidomyiidae, Eriophyidae) Leaf and twig gall
Data Maturity Structured Multiple sources. Expert review underway.