Micromeles Species, Korean Mountain Ash, Mountain Ash

This is a handsome, good-quality tree from China, Korea, and Japan. Its simple leaves are beech-like or hornbeam-like. I passed by a plan...Read Moreted specimen about 20 feet high in a front yard in southeast PA (zone 6b) for years and thought it was a European Hornbeam until I just saw the white flower clusters in late April. I think the hardiness range is wrong on this page. It should be USDA Zones 4 & 5 as best, 6 and 7 are workable. Still, it does not like summer heat and drought like other Mountainash, though it handles that a little better than the others. It can suffer from borers and fireblight disease also. Like others of the genus, it should not be used in tough, urban situations as narrow street parkways. My fear with any Eurasian woody plants in North America is that if they find a region really good for them they can escape cultivation and become invasive. That would be farther north in the US like New England or MN, WI, MI, etc. Around Chicago and the Midwest farther south I would not worry. It is not commonly planted or known in NA.

There's a beautiful mature specimen in the Arnold Arboretum, Boston, MA Z6a that never shows any problems. Excellent form, grows large (t...Read Moreo 50'). A beautiful 4-season shade tree.

Showy white May flowers, though in mature trees they're up high in the canopy. Gold to scarlet fall color can be outstanding. Showy scarlet fruit holds late into the winter, till the birds take them, and beautiful silvery beech-like bark.

Most mountainashes are small, short-lived trees, but this species is resistant to borer, lives much longer, and grows much larger than the others here in eastern Massachusetts.

This species is one of the Elizabeth Cary Miller Botanical Garden's Great Plant Picks, designed to promote the best plants for gardens of the maritime Pacific Northwest.

No mountainash tolerates hot summers or flourishes in eastern North America south of Z7.

Very invasive. We cut down the 44 trees in our Allée.

This fine tree has done well for us here on the south shore of Lake Superior. It is rather slow-growing, like all mountain ashes (perhap...Read Mores ten feet in ten years). The foliage is handsome in three seasons. You do need to protect it from deer in winter until it's tall enough to manage on its own. We pound in steel fenceposts and wrap snow fencing around it each fall and remove them in the spring. The tree is well worth the effort.