Japanese Alder
Alnus japonica
Betulaceae · broadleaf deciduous tree · introduced
Last updated
Plant Profile
Size & Form
Height
80 ft
Spread
8-12 ft
Growth Rate
Fast
Site Requirements
Light
Full Sun to Part Shade
Soil Drainage
Wet Tolerant
Soil pH
4.5-8.5
Water
High
Hardiness
Zones 5a–8b
Ornamental Interest
Bloom Time
March
Origin
far eastern Russia, China (Anhui
Watch for this season
Powdery MildewHigh
Active Conidial Spread
RustHigh
Uredinial Stage (Summer)
AphidHigh
Peak Population & Dispersal
Fall webwormHigh
Larval Feeding & Web Building
+ 3 more — see full disease and pest lists below
Diseases: Regionally Documented (11)
Armillaria spp. — primarily A Armillaria Root Rot Brown Leaf Blotch [VERIFY] Canker and Stem Diseases Viral agents Catkin Hypertrophy and Leaf Curl Collar Rot Lonsdalea quercina subsp Drippy Dieback Symptom category — not a single disease Leaf Spot Neonectria ditissima Nectria Canker Phytophthora spp. (P Phytophthora Root Rot Multiple obligate biotrophic fungi (Erysiphales: Erysipha... Powdery Mildew Multiple genera (Melampsoridium, Thekopsora, Naohidemyces... Rust
Pests: Regionally Documented (7)
Data Maturity Structured Multiple sources. Expert review underway.