Mountain Ash trees add great ornamental interest to residential yards, offering beauty throughout the growing season. Decorative flowers in the spring, berries with autumn foliage in the fall as well as handsome bark are characteristic of these small trees. They contribute continuing interest to the landscape. They are deciduous trees, losing their leaves in the fall. Some mountain ashes are native to northeastern North America, while some come to us from Asia and Europe. They are all fast growers. Showy Mountain Ash (Sorbus decora) is one of the best from this country. It is basically a northern, higher altitude version of its cousin the American Mountain Ash (Sorbus americana) with which it shares many characteristics.