Index / Search / Quercus douglasii
§1 Plant
Quercus douglasii Hook. & Arn.
vernacular blue oak — species · Fagaceae
§2Habit & range
Habit and range
- Growth habit
- Tree
- Duration
- Perennial
- Group
- Dicot
- Family
- Fagaceae Dumort.
- Genus
- Quercus
§2a
Native status, by region
- L48 Lower 48 States Native
§2b
County-level range
· 42 counties across 1 state§3Cultivation specs · USDA
Recorded by the USDA Plant Materials Program.
§3a
Tolerances
- Drought
- High
- Shade
- High
- Moisture use
- Low
- Fire
- Low
- Salinity
- None
- Anaerobic
- None
- CaCO₃
- None
- Hedging
- None
§3b
Climate & soil
- Cold tolerance
- 10 °F minimum
- Frost-free days
- 150 min.
- Precipitation
- 10–60 in/yr
- pH range
- 4.5–7.5
- Root depth
- 32 in min.
- Fertility need
- Low
- Soil texture
- coarse, medium
§3c
Form & growth
- Growth form
- Single Stem
- Growth rate
- Slow
- Lifespan
- Long
- Mature height
- 60 ft
- Height @ 20 y
- 16 ft
- Foliage texture
- Coarse
- Foliage colour
- Gray-Green
- Porosity (summer)
- Moderate
- Porosity (winter)
- Porous
- Flower colour
- Yellow
- Fruit colour
- Brown
- Fire resistant
- No
- N fixation
- None
- Toxicity
- None
§3d
Reproduction
- Bloom period
- Spring
- Seed abundance
- Medium
- Seed begins
- Summer
- Seed ends
- Fall
- Spread rate
- Slow
- Stratify
- No
- Seeds / lb
- 100
- Propagation
- seed, bare root, container
§3e
Use & availability
- Commercial availability
- Contracting Only
- Nursery stock
- No
- Browse palatability
- Low
- Palatable, human
- Yes
- Lumber
- No
- Fuelwood
- High
- Christmas tree
- No
§4Counties, by state
Recorded in 42 counties across 1 state.
California view state ↗ 42 N ▾
- Alameda 06001
- Amador 06005
- Butte 06007
- Calaveras 06009
- Colusa 06011
- Contra Costa 06013
- El Dorado 06017
- Fresno 06019
- Glenn 06021
- Kern 06029
- Kings 06031
- Lake 06033
- Los Angeles 06037
- Madera 06039
- Marin 06041
- Mariposa 06043
- Mendocino 06045
- Merced 06047
- Monterey 06053
- Napa 06055
- Nevada 06057
- Placer 06061
- Plumas 06063
- Sacramento 06067
- San Benito 06069
- San Joaquin 06077
- San Luis Obispo 06079
- San Mateo 06081
- Santa Barbara 06083
- Santa Clara 06085
- Shasta 06089
- Solano 06095
- Sonoma 06097
- Stanislaus 06099
- Sutter 06101
- Tehama 06103
- Trinity 06105
- Tulare 06107
- Tuolumne 06109
- Ventura 06111
- Yolo 06113
- Yuba 06115
§5Sources & provenance
USDA PLANTS
Symbol, taxonomy, distribution, cultivation specs, native status. Public domain.
plants.usda.gov/QUDO ↗GBIF Backbone
Canonical taxonomic identity, synonym resolution, cross-refs. CC0.
gbif.org/species/2878266 ↗Record version
Cached and built locally. Source version on this record:
usda-plants-mt-2026-05-26
fetched 2026-05-26T20:46:58Z