Fraxinus sieboldiana aka Chinese Flowering Ash

Fraxinus sieboldiana is a deciduous tree in the olive family. Common names include Siebold ash and Japanese flowering ash. Its native range spans southeastern China, Korea, and central and southern Japan. It grows in woods on hills and mountain slopes. It also grows beside streams in ravines. These habitats lie at 1,640–3,940 feet [500–1,200 metres] above sea level.

In gardens, it forms a large shrub or medium tree. It reaches about 20–30 feet [6–9 metres] tall. Plants For A Future gives a height of 26 feet [8 metres]. Its growth rate is moderate, with an upright form. The young branches are thin and bear upright hairs. Leaves grow in opposite pairs along the stems. Each pinnate leaf reaches about eight inches long. It has five to seven leaflets with sharply pointed tips. Leaflet edges may be toothed or smooth. Their surfaces lack hairs, but the midrib has downy hairs.

White flowers form loose clusters up to six inches long. Oregon State places bloom in late spring to early summer. Plants For A Future gives June, though its summary says late summer. This ash has petals, unlike many other ash species. Male and female flowers grow on separate plants. Wind carries the pollen, according to Plants For A Future. Both sexes must grow nearby for seed production. The winged fruits measure about an inch long. Their wings broaden toward the tip. Seeds ripen from September to October.

Grow this tree in sun and moist soil. It accepts sand, loam, and clay, but prefers deep loam. Its soil range spans mildly acid through mildly alkaline conditions. Plants For A Future reports tolerance of strong winds and air pollution. It lists USDA hardiness zones 6–9. Oregon State also places its cold limit at zone 6. These traits support its use as a specimen tree. Its flowers and compound leaves provide interest in garden plantings.

The wood is light, soft, and elastic. People use it for furniture and utensils. Plants For A Future lists no known edible or medicinal uses. It also reports no known hazards. That does not establish that all parts are safe to eat. The supplied evidence gives no species-specific account of pests or diseases.