Whitebeam Mountain Ash

Sorbus aria

Rosaceae · broadleaf deciduous tree · introduced

Last updated May 24, 2026

Plant Profile

Size & Form

Height

35–45 ft

Spread

26 ft

Growth Rate

Medium

Site Requirements

Light

Full Sun

Soil Drainage

Moist

Soil pH

4.5-8.5

Water

Moderate

Hardiness

Zones 5a–8b

Ornamental Interest

Bloom Time

may to june

Origin

Europe, long cultivated

Cytospora CankerHigh

Peak Spore Production and Dispersal

Fire BlightHigh

Bloom Infection Window

RustHigh

Uredinial Stage (Summer)

Peak Population & Dispersal

+ 2 more — see full disease and pest lists below

Diseases: Regionally Documented (5)

Cytospora spp. (Valsa spp., Leucostoma spp.) Cytospora Canker Erwinia amylovora Fire Blight Symptom category — not a single disease Leaf Spot Neonectria ditissima Nectria Canker Multiple genera (Melampsoridium, Thekopsora, Naohidemyces... Rust

Pests: Regionally Documented (9)

Aphidoidea Aphid Choreutis pariana Apple-and-thorn skeletonizer Enarmonia formosana Cherry bark tortrix Pristiphora geniculata Mountain ash sawfly Pear sawfly (pear slug) Leaf blister mite Otiorhynchus spp. Root weevil Malacosoma spp. Tent caterpillar Ash borer

Data Maturity

Structured Multiple sources. Expert review underway.