UI Arboretum Logo

University of Idaho Logo
The Flowering Season Arboretum Associates Volunteer Opportunities

About UI Arboreta

Collections and Gardens

Seasonal Attractions

Use Policies

Membership and Giving

tour maps
Bulletin Board

seasonal attractions

Plant of the Month

Korean Mountain Ash
Sorbus alnifolia

Location: Grid X2 north east corner of the Arboretum, west of the new peony beds

There are lots of different Mountain Ashes (Wikipedia is not very helpful here, saying between 100 and 200 species in the genus Sorbus...). The most common ornamental species in our area is the European Mountain Ash, Sorbus aucuparia, which usually has showy orange/red berries in large clusters. They generally remain on the tree until late winter when flocks of Cedar Waxwings will descend on the trees and strip the berries.

Korean Mountain Ash 10-16-14
Korean Mountain Ash 10-16-14

A less common species in our area is the Korean Mountain Ash, Sorbus alnifolia. It really has little resemblance to either the European Mountain Ash or our two native species. The leaves are entire rather than compound and the berries are much larger and pink ripening to red.

Korean Mountain Ash 10-16-14
Korean Mountain Ash 10-16-14

The three trees in the group in the photo are a good example of genetic diversity. All three trees were grown from seed collected near Beijing, China. The tree in the photo has vivid red fall color, the other two are distinctly different, exhibiting various shades of orange fall color.

Monthly Projects

October usually gives us a little window of opportunity between mowing and irrigation and fall clean up and winter protection. We try to take advantage of that window to get things done that get postponed the rest of the year. The big project for this month has been attempting to restore the bronze plaques in the Arboretum. I have tried several products and combinations of products in the past with very little success. We are trying a new combination and at least the initial results have been far better than earlier attempts. There are 153 bronze plaques scattered throughout the site; so, it has taken some significant time, but we are nearing the finsh line.

Before bronze plaque restoration 10-8-14
After bronze plaque restoration 10-8-14
Before and after bronze plaque restoration 10-8-14

We have also done some fall planting, beginning planting in the Joy Passante Peony Walk in the north east corner, and the Mary Voxman American Hydrangea collection on the east side of the stream in the lower third of the site, along with a new Hosta bed in the Beth Bowler Hosta Walk.

Upcoming Events


Arboretum Associates Annual Plant Sale
Saturday, May 30 2015 9:00 am to 12:00 pm
Ice Rink at the Latah County Fairgrounds

Peony 'Coral Sunset'
Peony 'Coral Sunset'

Main | About UI Arboreta | Collections & Gardens | Seasonal Attractions | Use Policies
Red Barn Gift Shop | Membership & Giving | Tour Map | The Flowering Season
Arboretum Associates | Volunteer & Internship Program | Email Us

University of Idaho Arboretum & Botanical Garden © 2014 all right reserved