tree

Grey alder

Alnus incana

Updated 8 Jul 2026 · AI-parsed entry

Grey alder (Alnus incana) — a tree, for Full sun, Medium water.

What it needs & gives back

↓ Needs

Sunlightfull sun to partial shade
Watermedium to high

↑ Gives back

Biomassmedium to high
Shademedium

Through the year

Emergence

Bud break and leaf emergence typically occur after the last spring frost and when air temperatures consistently rise above 5°C.

Flowering

Flowering occurs in early spring, usually in March, as days lengthen before leaf emergence.

Fruiting

Fruits (small cones) develop over the summer, maturing approximately 4 months after flowering.

Senescence

Leaves turn yellow and drop in autumn, triggered by the first frost and shortening day lengths.

Dormancy

The tree enters dormancy after the first autumn frost, remaining dormant through winter.

Timing is relative to your local season (temperate Northern Hemisphere).

Soil interactions

Drainagemoist to wet
Nitrogen fixingYes
MycorrhizalYes
Accumulatesnitrogen, calcium, magnesium
Soil textureloam, sand, clay
Organic matterHigh
Compaction toleranceMedium

Propagation

Methodsseed, cuttings, layering
Difficulty2 / 5
Establishes in~2 yr
Stratificationrequires cold stratification for 60-90 days
Self-seedingModerate
Divisionnot applicable

Wildlife & pests

Attractspollinators, birds
Can host diseasesalder canker