The genus Syringa contains woody, deciduous perennial shrubs or small trees, commonly called lilacs, grown for their large, airy panicles of highly aromatic tubular blooms. Classic garden shrubs, lilacs bloom in spring or early summer in a range of colors, from dark purple to white, with some rose and magenta colors. The deliciously sweet-smelling flowers attract bees, butterflies, and hummingbirds and make excellent cut flowers for arrangements. Fruits (smooth, brown, 2-celled capsules) follow the flowers and ripen in late summer or fall, often persisting well into winter.
A member of the Olive family (Oleaceae), Syringa is a genus of about 25 to 30 recognized species that typically mature to between 8 and 12 feet tall, with a similar width. In optimal conditions, the multi-trunked, spreading shrub can grow even larger. There are also dwarf species available, which typically stay about 3 feet tall and wide. Hundreds of cultivars are grown, with the majority developed from S. vulgaris L. (common lilac), the longest blooming species in the genus, such as Syringa × chinensis (Chinese lilac), which is a cross between S. vulgaris and Syringa persica (Persian lilac). Syringa oblata, (early lilac or broadleaf lilac) is the only species that exhibits bright fall color.
Long-lived, lilacs are generally hardy and thrive in colder climates (Zones 3-7). Lilacs tolerate light shade but flower best in full sun. They grow well on a variety of soils having a pH between 6.0 and 7.5 but prefer moderately rich, moist soils with good drainage and aeration. Good air circulation and periodic fertilization help keep the plant healthy and disease free. Deadheading and proper pruning enhances flowering. Lilacs bloom on old wood, so pruning should be done immediately after flowering. Shrubs are deer resistant. Grow lilacs as specimens and accents or group in low-maintenance borders or privacy hedges.