Common Filbert
'Leaf emergence'Corylus avellana
Betulaceae · broadleaf deciduous shrub · introduced
Last updated
Plant Profile
Size & Form
Height
15 ft
Spread
9 ft
Growth Rate
Moderate
Site Requirements
Light
Sun to Part Shade
Soil Drainage
Well Drained
Soil pH
4.5-8.5
Water
Moderate
Drought Tolerance
Moderate
Hardiness
Zones 4a–8b
Ornamental Interest
Bloom Time
February to March
Fall Color
Yellow
Origin
Europe, Western Asia
Watch for this season
Powdery MildewHigh
Active Conidial Spread
Wood DecayHigh
Wound Infection Window
Armillaria Root RotModerate
Active Below-ground Growth
Sooty MoldModerate
Heavy Mold Colonization
+ 1 more — see full disease and pest lists below
Diseases: Regionally Documented (19)
Armillaria spp. — primarily A Armillaria Root Rot Pseudomonas syringae pv. syringae Bacterial Blight [VERIFY] Blanks Cryptosporella umbrina Brown Stain Symptom category — not a single disease Canker Catkin Blast Candidatus Phytoplasma pyri Decline/Collapse Syndrome Anisogramma anomala Eastern Filbert Blight Fungal agents (multiple) Kernel Molds Symptom category — not a single disease Leaf Spot Apple mosaic virus (ApMV) Mosaic Mosses and Lichens Multiple obligate biotrophic fungi (Erysiphales: Erysipha... Powdery Mildew Fumago vagans Sooty Mold Daffodil yellow stripe virus (DYVV) Stunt (Dilly) Sunburn Wet Feet Taphrina wiesneri Witches' Broom Multiple Basidiomycete fungi cause wood decay in trees Wood Decay
Pests: Regionally Documented (9)
Cnephasia longana Omnivorous leaftier Phenacoccus aceris Apple Mealybug Halyomorpha halys Brown marmorated stink bug Myzocallis coryli Filbert Aphid Phytoptus avellanae Filbert Bud Mite Archips rosanus Filbert Leafroller Cydia latiferreana Filbertworm Parthenolecanium spp. Lecanium scale Malacosoma spp. Tent caterpillar
Phenological Calendar
As of June 3, 2026, Puget Sound stations range from 2435.5 to 2672.8 GDD₃₂. Common Filbert has passed 'leaf emergence' (1345 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Jun 3, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,673 | 'Leaf emergence' | — | — |
| Kent / Auburn | 2,665 | 'Leaf emergence' | — | — |
| Seattle / UW | 2,610 | 'Leaf emergence' | — | — |
| Olympia / Tumwater | 2,570 | 'Leaf emergence' | — | — |
| Tacoma / Puyallup | 2,535 | 'Leaf emergence' | — | — |
| Bellingham / Whatcom | 2,533 | 'Leaf emergence' | — | — |
| Sequim / Rain Shadow | 2,436 | 'Leaf emergence' | — | — |
View full calendar (2 stages)
| Stage | GDD32 | Typical Window |
|---|---|---|
| 'Bud break' BBCH '07' | 1187 | '' |
| ● 'Leaf emergence' BBCH '11' NOW | 1345 | '' |
Source: 'NPN citizen science observations (WA+OR), n=5, median. services.usanpn.org' About GDD₃₂ →
Season tracker for Kent / Auburn as of Jun 3, 2026. Predicted dates use 16-day weather forecast through Jun 19, 2026, then climate normals.
Cultivars (4)
'Contorta'
Common name: Contorted Filbert Contorted Hazelnut Harry Lauder's Walking Stick; Mature height: 8–10 ft
Hardy to USDA Zone 4
'Red Dragon'
Common name: Red Dragon Hazelnut
Hardy to USDA Zone 4
'Red Majestic'
Common name: Red Majestic HazelnutRed Majestic Filbert
Hardy to USDA Zone 4
'Rote Zeller'
Common name: Rote Zeller Hazelnut
Hardy to USDA Zone 4
Data Maturity Structured Multiple sources. Expert review underway.