Also known as Alniaria alnifolia and Aria alnifolia.
Medium-sized (30-50 feet tall, 20-30 feet wide) ornamental tree in the rose family.
Fast-growing, changing from a pyramidal shape to a more rounded one as it matures
Flowers and fruits attract birds and pollinators
Dark green, simple, lanceolate leaves are shiny and slightly hairy, about 3-6 inches long.
Large, white flowers bloom in the summer and fruits ripen in the early fall.
Requires acidic, well-drained soil and full sunlight
USDA Hardiness Zone 3-8.
Sentimental and Symbolic Value
It is called 水榆花楸, "water elm rowan" in Chinese, and its bark is widely used in China for wooden appliances and art, its bark in dyes, and its fiber in traditional papermaking.
Mountain ash and rowan trees figure significantly into the mythology of pagan European peoples such as the Sámi, who hold that it is sacred to the goddess Ravdna.
Some neo-pagan beliefs hold that it is a "portal tree" which can take one between human and spiritual realms.
Specimen photographed found at the Arnold Arboretum, Boston, Massachusetts. Part of the Ornamental Trees assignment (11/3/2021).
Plant History and Etymology
Sorbus is a Latin word of unknown etymology, which refers to sorb trees and berries. Similar to Frangula alnus, the specific epithet refers to the alder tree, which has similar leaves to this plant. It is native to Korea, Japan and China, where it was grown as an ornamental for centuries. It was brought to the West in the 19th century and became a somewhat uncommon, but very attractive ornamental. Its taxonomy is contentious, with some considering it part of the Sorbus genus with other sorb-trees, others placing it in Alniaria with the whitebeams, and others wanting to place it in its own genus called Micromeles, due its leaf shape and fruit biology being very different from other whitebeams and sorb-trees.
Design Considerations
Sorbus alnifolia is overall a very attractive and showy tree all year round. Its leaves turn to various shades of gold and brown in the fall and its large white flowers are visible through most of the late spring and summer. These flowers are grouped in dense, flat corymbs which are made up of multiple 1-3" flowers. The berries, which ripen in the fall, range in color from pink to scarlet and persist on the tree throughout the winter, even after the leaves fall. Its bark is smooth and light gray in color, generating additional winter interest. Its formal, rounded shape, minimal pruning requirements, and year-round visual interest make it a good choice for an ornamental garden, a winter garden, or any low-maintenance planting.
Sources
“Sorbus Alnifolia (Korean Mountain Ash, Mountain Ash) | North Carolina Extension Gardener Plant Toolbox.” 2021. Ncsu.edu. 2021. https://plants.ces.ncsu.edu/plants/sorbus-alnifolia/.
“Sorbus Alnifolia - Plant Finder.” 2021. Missouribotanicalgarden.org. 2021. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=286598&isprofile=0&.
Rushforth, Keith. 2018. “The Whitebeam Problem, and a Solution.” Phytologia 100 (4): 222. https://www.phytologia.org/uploads/2/3/4/2/23422706/100_4_222-247rushforthmalinae__rosaceae_12-5-18.pdf.
Gorman, Jim. 2021. “Korean Mountainash, Sorbus Alnifolia | Mount Auburn Cemetery.” Mountauburn.org. 2021. https://mountauburn.org/horticulture-highlight-korean-mountainash-sorbus-alnifolia/.
“Sorbus Alnifolia in Flora of China @ Efloras.org.” 2021. Efloras.org. 2021. http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200011662.
“水榆花楸_百度百科.” 2018. 百度百科. 2018. https://baike-baidu-com.translate.goog/item/%E6%B0%B4%E6%A6%86%E8%8A%B1%E6%A5%B8/8882748?_x_tr_sl=zh-CN&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=nui,sc.