Greene's Mountain-Ash

Sorbus scopulina

Rosaceae

• Keystone plant
• Spokane Native
• Sun-Shade
• Size: 3'-15’ tall x 6’-12' wide
  
• Drought Tolerant: Yes
• Evergreen: no
• Flower Color: white (March - July)
• Wildlife Value: birds, insects, and mammals

Greene's Mountain-Ash (also called Cascade Mountain-Ash, Rocky Mountain Mountain-Ash, or Western Mountain-Ash) is a deciduous shrub or small tree native throughout western North America from Alaska and Northwest Territories south through British Columbia to California's Sierra Nevada and east to Montana, Wyoming, the Dakotas (including Black Hills), Colorado, Utah, New Mexico, and Nevada, occurring in canyons, wooded slopes, stream banks, and rocky hillsides from 4,000-9,000 feet elevation (sea level in northern portions). The common name honors American botanist Edward Lee Greene (1843-1915). Species name "scopulina" means "of rocky places" or "of the rocks/cliffs," perfectly describing its preferred habitat on rocky alpine sites and mountainous terrain. This highly variable species forms dense thickets and typically grows 3-15 feet tall as a shrub (rarely to 25 feet; most commonly attains small tree form up to 20 feet only in southeastern Alaska). On rocky alpine sites at higher elevations often only 1-2 feet tall (krummholz form). Bark is thin, smooth, gray or reddish. LEAVES are pinnately compound, 10-23 cm (4-9 inches) long with 9-15 leaflets (sometimes 9-13), each leaflet lanceolate, 3-6 cm long with rounded base, acute apex, and serrate margins for almost entire length—leaves are shiny dark yellowish-green above, slightly paler below, turning attractive golden-yellow to brilliant orange-red in autumn (spectacular fall color). FLOWERS are borne in large terminal flat-topped clusters (corymbs) with 70-200 fragrant small white-to-cream flowers, each approximately 10 mm wide with 5 rounded white petals, 15-20 stamens, 3-4 styles—blooming March through July depending on elevation/latitude. Flowers are pollinated by insects. FRUITS are small orange-to-red glossy pomes (berry-like) about 10 mm (1/2 inch) diameter, ripening late summer/fall and PERSISTING INTO WINTER—this persistence makes fruits critically valuable to wildlife during harsh months when other food sources depleted. Fruits are bitter/astringent when raw but edible to humans when cooked (though care needed to distinguish from poisonous baneberries which can resemble Mountain-Ash). Throughout Cascade Mountains and Pacific Northwest, commonly called Cascade Mountain-Ash (sometimes listed as var. cascadensis). Variety cascadensis occurs mostly on west slope of Cascades, Olympic Mountains, and Sierras; intermediate forms on east Cascades and Wallowa Mountains. Species hybridizes with Western/Sitka Mountain-Ash (S. sitchensis). Rare natural hybrid Amelasorbus jackii (cross between Amelanchier alnifolia and S. scopulina) observed in Oregon and Idaho. Not to be confused with true Ashes (Fraxinus genus—unrelated). Mountain-Ash also known as Rowans, Whitebeams, Service Trees—name "Rowan" from Norse word for tree or Germanic "getting red" (referring to fall foliage/berries). Rowans were sacred in Celtic mythology; wood used for Druid staffs, magic wands, dowsing rods.

KEYSTONE SPECIES - Fruits are CRITICALLY IMPORTANT food source for wildlife, especially valuable because they PERSIST through winter when other foods scarce.  Berries consumed by grouse (ruffed grouse, blue grouse, spruce grouse), grosbeaks (Evening Grosbeaks eagerly harvest), Cedar Waxwings, thrushes, robins, jays, various songbirds—critical late-season and winter food.  Seeds/fruits eaten by Douglas Squirrels, chipmunks, small mammals.  Twigs and foliage provide browse for moose, deer (mule deer, white-tailed deer, black-tailed deer), elk, mountain goats—moderately to highly palatable depending on region and season. Black bears and grizzly bears extensively consume berries, leaves, and stems (especially important in fall fattening before hibernation). Roosevelt elk utilize Mountain-Ash in summer months. Porcupines browse bark and foliage. Flowers attract and provide nectar for bees, butterflies, and diverse insect pollinators. Dense thickets provide cover, nesting sites, and thermal protection for birds and small mammals. High-elevation populations play CRITICAL ecosystem roles: maintaining diversity of wildlife/plant species, regulating snowmelt and runoff, providing cover on harsh high-elevation sites where little else grows. Seeds primarily dispersed by birds, aiding natural regeneration.

FRUITS were used by Native Americans and early settlers—despite resemblance to poisonous baneberries, Mountain-Ash fruits are EDIBLE when cooked (astringent/bitter raw). Indigenous peoples cooked berries and made them into jelly, preserves, or consumed after preparation. Early settlers similarly processed fruits. CAUTION essential to distinguish from red baneberry (Actaea rubra) which is poisonous—Mountain-Ash has compound pinnate leaves with many leaflets while baneberries have different leaf structure. Various tribes used plant parts medicinally though specific documentation for S. scopulina limited compared to related species. WOOD occasionally used for implements and tools. European Mountain-Ash (S. aucuparia—introduced, naturalized species) has extensive Old World folklore and uses: fruits processed into alcoholic drinks, juice, vinegar (used medicinally), tea; wood valued in European traditions. Greene's Mountain-Ash valued today primarily for ORNAMENTAL qualities (attractive flowers, brilliant fall color, showy persistent berries, multi-season interest) and WILDLIFE HABITAT value rather than for human consumption, though fruits technically edible when cooked.

LANDSCAPE USE AND COMPANIONS: Outstanding for wildlife gardens, pollinator gardens, naturalized landscapes, woodland gardens, mountain gardens, riparian plantings, erosion control on slopes, restoration projects, and high-elevation revegetation. Provides multi-season ornamental interest: fragrant white flower clusters (spring/early summer), shiny dark green compound foliage (summer), spectacular golden-yellow to orange-red fall color (autumn), persistent glossy orange-red berries decorating bare branches (fall through winter). Grows in full sun to light shade (adaptable). Prefers moist, rich soils but tolerates range of conditions. Grows on rocky hillsides, open woods, stream banks, canyons, alpine sites—usually in small clumps. Does best in sandy or loamy soils; does NOT grow well in heavy clay soils. Requires good drainage. Prefers slightly acidic to neutral soils; low calcium carbonate tolerance. Hardy to USDA Zone 2 (extremely cold-tolerant—Arctic hardy). Suitable for challenging mountain sites, harsh exposed locations, high elevations where few other plants thrive. Forms dense thickets over time through suckering. Begins producing seed around 15 years of age; usually produces good crops annually. Seedlings hardy and not very susceptible to insects/disease but may be injured by deer browsing (protect young plantings). Can be insect and disease prone when stressed—provide appropriate site conditions. Mature plants can be eliminated by severe fires, though seedlings/sprouts may appear first and second post-fire years. Propagate by seed (dispersed by birds in wild), division, or layering. Seeds require stratification. Plant with Subalpine Fir, Engelmann Spruce, Lodgepole Pine, Quaking Aspen, willows, Rocky Mountain Douglas-fir, Western Larch (high elevations); Ponderosa Pine, Douglas-fir, Grand Fir (mid-elevations); Serviceberry, Oceanspray, Thimbleberry, Snowberry, native Currants, native Roses, Red-osier Dogwood, other mountain shrubs depending on elevation and aspect. Particularly valuable in subalpine and alpine restoration where it provides critical wildlife food and cover in harsh environments. CONSERVATION NOTE: High-elevation five-needle pine decline (from white pine blister rust, mountain pine beetle, climate change) threatens associated wildlife including species dependent on Mountain-Ash as alternative/supplemental food source. Maintaining healthy Mountain-Ash populations increasingly important as pine ecosystems face challenges.