Possibly the most useful of the lilacs in landscape work is the tree lilac, known commercially as Syringa Japonica. As introduced from Japan it has not proven hardy in Iowa; but as introduced from east Europe it is quite as hardy as the common lilac. This makes a small tree that does not sprout from the crown. It has large dark-green leaves, and its large panicles of pure white flowers appear in June. A variety of this sproutless species from the Amur valley was received by the writer from Moscow, Russia, under the name of Syringa Amurensis. Its leaves are much larger than the typical species, and it flowers at the height of only four or five feet. The flowers are pure white, and appear on upright panicles above the large leaves.

The Josikea lilac, from Transylvania, also seems to be a closely related species. It does not sprout, and its leaves are large, dark green, free from mildew, and it is very hardy everywhere. Its flowers are delicate pink and appear in June. Of the smaller-growing bush species such varieties as Charles X, Marie Legraye, and Lemoine's double-flowered are more desirable than the old-fashioned red and white, as their foliage is better and also the flowers. They also flower when younger.

The Persian species {Syringa Persica) is not as stiff and formal in habit as the other species, and some of the improved varieties, such as the alba and laciniata, are valuable in landscape horticulture.