Culture
Best grown in consistently moist, well-drained soils (clay or sandy) in full sun. Tolerates light shade. Adapts to dry soil conditions. Winter hardy to USDA Zone 6.
Noteworthy Characteristics
Fraxinus sogdiana, commonly called Tianshan ash, is a medium-sized deciduous ash tree that typically matures to 30' (uncommonly to 60') tall. It is native to deciduous forests and along rivers in western China (W. Xingiang Province), Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan. This tree is included on the IUCN Red List of Threatened Species in the category of Near Threatened. Alternate, odd-pinnate, compound green leaves appear in whorls of three at the branch tips. Each leaf (to 10-15" long) features 7-11 glabrous lanceolate leaflets (to 3" long) with toothed margins. Leaves turn yellow in fall. Apetalous, greenish-yellow flowers appear in panicles before the leaves. Female flowers give way to winged samaras which mature in August-October in drooping clusters.
Genus name is the classical Latin name for ash trees.
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. Tianshan 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. 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
Tianshan ash is a threatened species that has been uncommonly planted in North America in the past. It is difficult to locate in commerce. Planting new ash trees (regardless of species) is no longer recommended given the apparent susceptibility of all ashes to the emerald ash borer.