Grey alder
Grey alder
Alnus incana
tree☀️ full-sun🪴 moist-loam📏 medium🌡️ RHS H7
⚠️ Invasive
📋Quick Facts
Height
12.0-20.0m
Spread
7.0-10.0m
Growth
🐢 Slow
Takes time to establish
Care Level
😊 Easy
Great for beginners
Water
💧💧💧 Frequent watering
Every "7-10" days
Hardiness
Zone 2-6
About
Fast-growing pioneer species for damp sites.
Top tip
Grey alder is a pioneer tree; use on poor or disturbed sites to build fertility and structure.
Also known as: Olsza szara, Amieiro-branco / cinzento, Ontano grigio, Grauwe els, Aulne blanc / gris, Grauerle, Aliso blanco / gris, Alnus incana
Pest Resilience
4/5 — Good resilience
Few pest problems; phytophthora root disease is the main risk in wet soils.
Visual Characteristics
🌲
Cones
Produces cones
The grey alder year in your garden
Dispatching imaginary bots to check your garden out...
What to do now
How to Propagate
🌰Seed
Easy🌿Layering
Moderate✂️Cutting
Moderate🔗Grafting
Advanced🦋Wildlife & Garden Ecology
Attracts
🐦 Birds
Great for supporting local pollinators and wildlife
Hardiness Zones
H1a (tender)H7 (very hardy)
RHS H7
USDA 4–5 equivalent