Lilac, an ornamental flowering shrub, the name of which is said to have been introduced with the plant. It belongs to the genus syringa, of the olive family; the generic name is from the Greek for pipe or tube (ovpiye), on account of the tubular form of the flowers, or according to some because the wood is used for pipe stems; this latter seems the more probable, as a century ago the lilac and the shrub now cultivated as the mock orange (Philadelphus coronarius) were both known in English gardens as pipe tree; it is singular that the botanical name for the lilac is retained as one of the popular names for Philadelphus, which is frequently called syringa. The lilac has opposite leaves with scaly buds in the axils, but a terminal bud is rarely formed, so that each branch has a pair of buds at its tip The flowers, which appear in early spring, are in large pyramidal panicles, and are delightfully fragrant; the corolla has a long tube, with a salver-formed, four-lobed limb; stamens two, attached to the tube of the corolla; fruit a two-celled capsule, with one or two slightly winged seeds in each cell.
The best known species is the common lilac (8. vulgaris), which was formerly supposed to be exclusively a native of Persia, but it is also found wild in eastern Europe; it was introduced into European gardens in 1597 by way of Constantinople. As commonly seen in old gardens, the lilac forms a dense thicket on account of the numerous suckers it produces, but if these are kept subdued it may be made to form a tree 20 ft. or more high, with a clear trunk; it is not regarded as a long-lived tree; it has been used to form hedges, but is objectionable from its tendency to spread. The suckers afford a means for readily propagating the plant, but new varieties are obtained by seed. The normal color of the flowers is a pale dull blue, with a slight admixture of red, known in the nomenclature of tints as lilac color; the varieties are white, red, violet, etc, and there are those with double flowers; among the finest varieties is that known as Charles X., with enormous panicles of the finest color. The Persian lilac (8. Persica) is a small slender shrub, from 3 to 6 ft. high, with lance-ovate leaves and looser clusters of flowers, of a paler color than the common; there is a white variety of this and varieties in which the leaves are much cut and divided.
Josika's lilac (8. Josikcea) has wrinkled and darker foliage than the common, and bluish-purple flowers without odor, and blooms much later than any of the forms of 8. vulgaris, to which species some are disposed to refer it. A Himalayan species, S. Emodi, is in cultivation, but not superior as an ornamental plant to the best forms of the common lilac. Another doubtful species, 8. dubia, which has also received the name of 8. Rotho-gamensis, is by some considered a hybrid between the common and the Persian. As ornamental garden shrubs all the lilacs are popular, and are hardy and easily managed. In France the lilac is largely used for forcing, the clusters of white lilacs being very popular as winter flowers and for holiday presents. The forcing is done in board structures with a strong artificial heat; the flowers develop in the dark, and the varieties are used indiscriminately, as when produced under these conditions the flowers of all are white.
Charles the Tenth Lilac.