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American Green Alder

Alnus alnobetula subsp. crispa

Betulaceae · broadleaf deciduous shrub · introduced

Last updated March 8, 2026

Data Coverage 2 of 6 dimensions
Site Data
Threats
Cultivars
Phenology
GDD Thresholds
Puget Sound

Quick Facts

Height
3–13 ft
Light
Full Sun to Shade
Hardiness
Zone Zones 1a–8b

Diseases (11)

Armillaria ostoyae Armillaria Root Rot [VERIFY] Brown Leaf Blotch [VERIFY] Canker and Stem Diseases Viral agents Catkin Hypertrophy and Leaf Curl Phytophthora cactorum 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 Podosphaera aphanis var. aphanis Powdery Mildew Thekopsora minima and Naohidemyces vaccinii Rust

Pests (7)

Aphidoidea Aphid Hyphantria cunea Fall webworm Chrysomelidae: Alticini Flea beetle Malacosoma spp. Tent caterpillar Altica ambiens Alder flea beetle Various (Agromyzidae, Gracillariidae, Tenthredinidae) Leafminer Malacosoma californicum Western tent caterpillar

Also Known As

  • Mountain Alder
  • Green Alder

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Pesticide recommendations are for reference only. Always read and follow the label.

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