Alder

Frangula alnus

Rhamnaceae · broadleaf deciduous shrub · introduced

Last updated March 9, 2026

Plant Profile

Size & Form

Height

15 ft

Spread

13 ft

Growth Rate

Fast

Size at 20 yr

12 ft

Lifespan

Moderate

Site Requirements

Light

Full Sun

Soil Drainage

Adaptable

Soil pH

5.0-6.5

Water

Moderate

Drought Tolerance

Medium

Hardiness

Zones 3a–8b

Ornamental Interest

Bloom Time

mid spring

Fall Color

Yellow

Origin

Europe, western Asia and North Africa

Diseases: Regionally Documented (1)

Symptom category — not a single disease Leaf Spot

Phenological Calendar

View full calendar (7 stages)

Stage	Typical Window	What to Look For
Bud break BBCH 07	Feb 15-Mar 15	Buds swelling and beginning to open; first green tissue visible
Leaf emergence BBCH 11	Mar 1-Apr 1	First leaves fully unfurled on new growth
Bloom start BBCH 61	Apr 1-Apr 30	First open flowers visible; flowers yellow
Bloom end / petal fall BBCH 69	Apr 15-May 15	Last petals falling; flower structures fading
Fruit/seed development BBCH 71	Jun 1-Aug 31	Fruit or seed structures forming; fruit color: red
Leaf drop BBCH 93	Oct 15-Nov 30	Leaves yellowing and dropping; no significant fall color display
Dormancy BBCH 97	Nov 15-Feb 28	Leafless; no active growth; dormant buds set

Cultivars (2)

'Asplenifolia'

Common name: Asplenifolia Alder Buckthorn; Mature height: 10 ft

Hardy to USDA Zone 3

'Fine Line'

Common name: Fine Line Alder Buckthorn; Mature height: 5–7 ft

Hardy to USDA Zone 3

Data Maturity

Structured Multiple sources. Expert review underway.