The lilac (Syringa) is a widely recognized deciduous shrub that heralds the arrival of spring in temperate climates. It is popular as an ornamental plant due to its spectacular, fragrant floral display. To identify a lilac bush, one must examine its distinct physical structure, characteristic foliage, and signature blooms.
Defining Physical Structure and Bark
The common lilac (Syringa vulgaris) typically grows as a multi-stemmed, upright shrub, reaching heights between 8 and 15 feet. It often spreads equally wide, forming a dense, rounded crown. Lilacs develop a thicket-like appearance because they produce new shoots, known as suckers, from the base and roots. This growth habit results in a cluster of stout, spreading branches rather than a single trunk.
The bark changes significantly as the plant matures. Younger stems are relatively smooth and grayish-brown or greenish-brown. On older, established stems, the bark becomes more textured and rugged. It develops longitudinal furrows and often appears flaky, peeling off in small plates or strips.
Characteristics of Lilac Foliage
Lilac leaves are simple, meaning they are not divided into smaller leaflets, and are arranged in opposite pairs along the stems. The most common species feature a cordate, or heart-shaped, leaf shape, though they can also be ovate. These leaves typically measure between 2 and 5 inches in length.
The foliage has a smooth, non-hairy texture and a consistent, matte green to dark green color throughout the growing season. The margins of the leaves are entire, lacking any teeth or lobes. Unlike many other deciduous shrubs, lilac leaves offer little dramatic color change in the autumn, generally remaining green until they turn a muted yellowish-brown before dropping.
The Signature Blooms and Fragrance
The most distinctive feature of the lilac bush is its flowers, which emerge in late spring or early summer after the leaves have unfurled. The blooms are borne in large, upright clusters known as panicles, which form at the tips of the previous year’s growth. These conical clusters are dense and showy, typically measuring between 4 and 8 inches long.
Each panicle is composed of numerous small, individual flowers, or florets, that are about one-quarter to one-half inch long. These florets have a narrow, tubular base that opens at the tip into four distinct, spreading lobes. While wild species are usually classic lilac or mauve, cultivated varieties display a wide spectrum of colors, including pure white, cream, magenta, pink, and deep purple.
The blooms are prized for their powerful and characteristically sweet fragrance, which can perfume a large surrounding area. This intense aroma is often described as a refined, floral scent with subtle, honeyed undertones. The strong fragrance, combined with the large, colorful panicles, makes the lilac bush unmistakable during its relatively short blooming period.