Common lilac is an introduced deciduous shrub with simple, smooth, heart-shaped, oppositely arranged leaves and 4 to 8 inch clusters of fragrant, purple to white flowers.
Common lilac is distinctive in having smooth (hairless) dark heart-shaped leaves which are arranged in opposite pairs, and twigs with opposite (lateral) buds, but no large terminal bud at the tip (so branches do not grow straight out). There are hundreds of varieties, but only a few closely related species. One (Syringa oblata) has rounded leaves (just as wide as long), and several species including the "Chinese" lilac (Syringa chinensis) which have leaves which taper at their base.
Did You Know?
Homesick settlers from Europe introduced common lilac. Bushes still can be seen thriving near abandoned pioneer homesteads. Ethnobotanical uses for the plant have been fever reducer, malaria treatment, perfume, tonic, and homeopathy.
The leaves are simple, smooth, and heart-shaped. They are 2 to 5 in (5 to 12.5 cm) long and dark green in color.
Common lilac has very conspicuous flowers. The small, fragrant, showy, flowers grow in clusters 4 to 8 in (10 to 20 cm) long. Generally, they are purple, lilac, or white in color.
As a non-native garden shrub, common lilac bushes only grow where they have been planted, such as in parks and gardens. They thrive in the eastern, Midwestern, and northern parts of the U.S. as they prefer areas with colder winters.
The greatest bloom is usually observed in the late spring, with fruit and seed production starting in the summer. In the middle of winter, common lilac buds are desiccated (dried out) and appear somewhat “shriveled.” In late winter, after conditions begin to warm, the buds hydrate (swell due to becoming moist) and the tips open slightly. Watching for these two events is the best way to know when to start daily observations looking for first leaf. Once the buds have swelled and bud ends are slightly open and a bit green, the next round of warm weather can force the first leaf event.