Culture
Best grown in consistently moist, well-drained loams (clay or sandy) in full sun. Tolerates light shade. Adapts to dry soil conditions. Performs poorly in climates south of USDA Zone 6.
Noteworthy Characteristics
Fraxinus mandshurica, commonly called Manchurian ash, is a medium to large deciduous tree that typically grows to 40-50' (less frequently to 100') tall with a dense, oval to rounded crown. It is native to wooded slopes and open valleys of northeast Asia and Japan. Pinnate compound leaves grow to 10-15" long, each leaf having up to 11 nearly stalkless, coarsely-toothed, lance-shaped leaflets (3-5" long). Leaflets are matt green above and downy on both sides, with distinctive sunken veins. Attractive yellow fall color. Non-showy, apetalous, greenish-yellow flowers in compact panicles begin bloom in spring before the leaves emerge. This tree is sometimes dioecious. Female flowers give way to winged samaras (1-2" long) which mature in August-October in drooping clusters. Manchurian ash is similar in appearance to Fraxinus nigra (black ash), and was once designated as a subspecies (Fraxinus nigra subsp. mandshurica).
Genus name is the classical Latin name for ash trees.
Specific epithet means of Manchuria.
Problems
Emerald ash borer is native to Asia. It was first discovered in the U. S. (southeastern Michigan) in 2002. It has now spread to a number of additional states in the northeast and upper Midwest, and is expected to continue spreading. Emerald ash borer will typically kill an ash tree within 3-5 years after infestation. Once infestation occurs, it is very difficult to eradicate this pest which feeds under the bark and bores into wood. This borer now constitutes a serious threat to all species of ash in North America. Manchurian ash may have some resistance to the emerald ash borer (tree and borer are both native to China), but supporting evidence is not well developed. Manchurian ash trees are generally susceptible to a number of additional insect problems including ash borer, lilac borer, cottony ash psyllids, carpenter worm, oyster shell scale, leaf miners, fall webworms, ash sawflies and ash leaf curl aphid. Potential disease problems include fungal leaf spots, powdery mildew, rust, anthracnose, cankers and ash yellows.
Uses
Manchurian ash has been uncommonly planted in many parts of North America in the past. Planting new trees is no longer recommended given the susceptibility of this tree to the emerald ash borer.