Western Mountain Ash

Sorbus sitchensis

Taxonomy

Division:
Magnoliophyta | - Flowering plants
Family:
Rosaceae
Genus:
Sorbus
Species:
Sorbus sitchensis

Growth Characteristics

Life Cycle:
Perennial
Growth Habit:
Shrub , Tree
Height:
12-20 ft
Light Requirements:
Full Sun, Part Shade, Shade
Drought Tolerance:
High
Bloom Months:
jun, jul
Bloom Colors:
White
Landscaping Shrub:
Yes

Native Range

United States: Alaska, California, Idaho, Montana, Oregon, Washington, Canada: Alberta, British Columbia, Yukon

Keystone Species Ranking

Caterpillar Keystone:
★★☆☆☆ Based on number of butterfly and moth species using this genus as host plant (Source: National Wildlife Federation)

Host Plant for Caterpillars

Acronicta superans, Barnes' dagger moth (Acronicta barnesii), Ceranemota crumbi, Radcliffe's dagger moth (Acronicta radcliffei), Western tent caterpillar (Malacosoma californica)

Reported Fauna Sightings

Bees: Black-tailed bumble bee (Bombus melanopygus), Black-tailed bumble bee (Bombus melanopygus), Fernald cuckoo bumble bee (Bombus flavidus), Fernald cuckoo bumble bee (Bombus flavidus), Yellow head bumble bee (Bombus flavifrons), Yellow head bumble bee (Bombus flavifrons)

Soil Requirements

Soil Type:
moist, well-drained, rocky or sandy soil
pH:
5.0 - 7.0 (slightly acidic to neutral)
Drainage:
excellent drainage required
Moisture:
consistently moist
Notes:
prefers cool, mountainous regions

Germination Information

Pre-treatment: Cold-moist stratification for 30 days at 1–5°C (34–41°F).; then Cold-moist stratification for 60 days.

Source: OpenAI GPT-4o