Syringa vulgaris (Syringa or Syringa vulgaris) is a flowering plant of olive family, which is native to Balkan Peninsula and grows on stony hills. This large shrub or small arbor is widely cultivated for its spring pink flowers and has been naturalized in parts of Europe and North America. It is not considered an invasive species and is usually found in the wild in widely dispersed areas near past or present human settlements.

Lilac is a large deciduous shrub or small multi stemmed tree that grows to a height of 6 – 7 m (20 – 23 ft). It produces secondary buds (suckers) from the roots or roots, with stems up to 20 cm (8 inches) in diameter, and may produce small clonal clumps over the course of decades. Bark is gray to grayish brown, smooth on young stem, longitudinal furrow, peeling off on old stem. The leaves are simple, 4 – 12 cm (2 – 5 inches) wide, 3 – 8 cm wide, light green to white, ovate to heart-shaped, pinnately veined, with short spikes and entire margins. They are arranged in pairs, or occasionally in pairs in three. Corolla tube base of flowers 6-10 mm long, with open tetrafid apex 5-8 mm, usually lavender to lavender, occasionally white. They are arranged in dense panicles 8-18 cm (3-7 in) long. The fruit is a dry, smooth brown capsule, 1-2 cm long, divided in two to release two winged seeds.

Lilac is a very popular ornamental plant in gardens and parks. Because of its attractive and sweet flowers, it appeared in early summer long before many roses and other summer flowers bloomed.

At the end of summer, lilac may suffer from powdery mildew, especially one of the family syringaceae. No autumn colors are seen, and the seed clusters have no aesthetic appeal.

Ordinary lilacs tend to bloom every other year, a habit that can be improved by removing clusters of flowers from their heads after the color has faded and before the seeds, which rarely reproduce, form. At the same time, the growth of twigs on buds that have already flowed more than once or twice can be cut into firm, outward growing lateral buds.

It has been widely naturalized in Western and Northern Europe. It was chosen as the state flower of New Hampshire, marking its complete naturalization in North America, because it "symbolizes the strong character of men and women in Granite State". Isabella Preston has planted a number of common streptococci, bringing more tolerance to Canadian gardens, which have introduced many late flowering varieties. Later buds can better protect themselves from the spring frost. The hybrid of Syringa × prestoniae was mainly pink and lilac.