Description & Overview

A Wisconsin native, Showy Mountainash provides true all-season interest in our northern climate. White spring flowers give way to bright red, eye-catching fruit clusters throughout summer. The tree has reliable fall color and the fruit persists during winter for birds. Not to be confused with a true Ash (Fraxinus species), this cold-hardy native is a great small-scale tree in the landscape.

Core Characteristics

Category: Tree

Wisconsin Native: Yes

USDA Hardiness Zone: to zone 3

Mature Height: 20-25 feet

Mature Spread: 15-20 feet

Growth Rate: Moderate

Growth Form: Rounded, small-scale tree

Light Requirements: Full Sun to Partial Shade

Site Requirements: Acidic preference, moist, well-drained soil

Flower: White spring flowers

Bloom Period: May

Foliage: Smooth blueish-green

Fall Color: Brilliant yellow

Urban Approved: No

Fruit Notes: Showy edible red fruit clusters

Suggested Uses

Site in well-drained or moist soils. Showy Mountainash prefers a slightly acidic location. Native mostly to northern Wisconsin, it naturally occurs around bluffs, upland forests swamps and shores (sandy or rocky sites). A great choice for an ornamental small-scale tree, Sorbus decora reaches mature heights at about 20-25ft. It can be used for screening, along roadways, or as a lawn specimen or small shade tree. It does not tolerate dry conditions. Profuse spring flowering gives way to beautiful bright red persistent berries that really catch the eye.

A Wisconsin native, Showy Mountainash provides true all-season interest in our northern climate. White spring flowers give way to bright red, eye-catc…

Wildlife Value

An important source of food for wildlife in winter and early spring, the persistent berries of Sorbus decora provide for non-migratory birds like Ruffed Grouse, Robins, Blue Jays, Starlings, Grosbeaks, Cedar Waxwings, Cardinals, Juncos, Chickadees, White-breasted Nuthatches, Purple Finches, and Swainson’s Thrushes.

Deer, moose, Snowshoe Hare, and rabbits prefer the leaves and twigs of Showy Mountainash.

It is a host plant to the Splendid Dagger moth (Acronicta superans), Spongy moth (Lymantria dispar), Eastern Tiger Swallowtail (Papilio glaucus), White Spring moth (Lomographa vestaliata), Three-spotted Sallow (Eupsilia tristigmata), Woody Underwing (Catocala grynea), Radcliffe’s Dagger (Acronicta radcliffei), Interrupted Dagger moth (Acronicta interrupta) and Clear Dagger moth (Acronicta clarescens).

The flowers are visited by honeybees, bumblebees, Syrphid Flies and beetles.

Maintenance Tips

Showy Mountainash is very intolerant of drought, so be sure to site accordingly. It prefers loamy soil and does well in the northern part of the state and if sited correctly can thrive elsewhere. Be sure to keep soil consistently moist when planting and choose a sunny or partial shade location.

Minimal pruning will be needed to maintain a good branching structure. Winter berries may fall onto nearby patios or sidewalks, but this is usually minimal as most are eaten by birds throughout the season.

Pests/Problems

A few issues may arise over the course of the tree’s life. Though long-lived there are some things to watch out for. Bacterial fireblight being the most common and detrimental, it causes scorched leaves towards the end of branches. Scab can also cause defoliation. Trees that are stressed by these diseases are more susceptible to insect issues like borers, aphids, sawfly and scale. Canker is also more commonly found in trees that already are under disease stress.

Leaf Lore

Edible for human consumption Showy Mountainash berries are mildly bitter but much more tolerable if cooked into a delicious jam. The common name Mountainash refers to the ash-like leaves and preference of a cooler, mountain climate. However, it is a member of the rose family and not the Fraxinus (our native Ash) species.

Companion Plants

A great tree to plant in rich loamy soils, combine with other natives that thrive in the same habitat. Try shrubs/trees like Pagoda Dogwood, Common Witchhazel, Scarlet Elderberry (Sambucus racemosa) and Musclewood in a mixed screen. Use native perennials like Canadian Columbine, Lady Fern, Canada Wild Ginger, Pennsylvania Sedge, Spikenard, Virginia Bluebells, Culver’s Root, and Giant Solomon’s Seal.

A Wisconsin native, Showy Mountainash provides true all-season interest in our northern climate. White spring flowers give way to bright red, eye-catc…
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Written by Johnson's Nursery