Syringa vulgaris

Syringa vulgaris, the lilac or common lilac, is a species of flowering plant in the olive family Oleaceae, native to the Balkan Peninsula, where it grows on rocky hills. Grown for its scented flowers in spring, this large shrub or small tree is widely cultivated and has been naturalized in parts of Europe, Asia and North America. It is not regarded as an aggressive species. It is found in the wild in widely scattered sites, usually in the vicinity of past or present human habitations.

Description

Syringa vulgaris is a large deciduous shrub or multistemmed small tree, growing to 6-7 m (20-23 ft) high. It produces secondary shoots from the base or roots, with stem diameters up to 20 cm (8 in), which in the course of decades may produce a small clonal thicket. The bark is smooth and greyish-brown on young stems. It can also be longitudinally furrowed on older stems. Flaking occurs on older stems. The leaves are simple, 4-12 cm (2-5 in) and 3-8 cm broad, light green to glaucous, oval to cordate, with pinnate leaf venation, a mucronate apex, and an entire margin. They are arranged in opposite pairs or occasionally in whorls of three. They have a tubular base that extends to the corolla measuring 6-10 mm in length and a four-lobed open apex measuring 5-8 mm across. The flowers are usually lilac or mauve but can also be white. They are arranged in terminal panicles that measure 8-18 cm (3-7 inches) in length. The fruit is a dry, smooth, brown capsule, 1-2 cm long, splitting in two to release the two-winged seeds.

Cultivation

The lilac is a very popular ornamental plant in gardens and parks, because of its attractive, sweet-smelling flowers, which appear in early summer just before many of the roses and other summer flowers come into bloom.

In late summer, lilacs can be attacked by powdery mildew, specifically Erysiphe syringae, one of the Erysiphaceae. The seed clusters are not attractive and there is no fall color.

Common lilac tends to flower profusely in alternate years, a habit that can be improved by deadheading the flower clusters after the color has faded and before seeds, few of which are fertile, form. At the same time, twiggy growth on shoots that have flowered more than once or twice can be cut to a strong, outward-growing side shoot.

It is widely naturalised in western and northern Europe. In a sign of its complete naturalization in North America, it has been selected as the state flower of the state of New Hampshire, because it “is symbolic of that hardy character of the men and women of the Granite State”. Additional hardiness for Canadian gardens was bred for in a series of S. vulgaris hybrids by Isabella Preston, who introduced many of the later-blooming varieties. The late-developing flower buds of these hybrids are more resistant to frost damage in the spring. The Syringax prestoniae hybrids are primarily available in pink and lavender colors.

Cultivars

Most garden plants of S. vulgaris are cultivars, the majority of which do not exceed 4-5 m (13-16 ft) tall. Between 1876 and 1927, the nurseryman Victor Lemoine of Nancy, France introduced over 153 named cultivars, many of which are considered classics and still in commerce today. Lemoine’s “French lilacs” extended the limited color range to include deeper, more saturated hues, and they also introduced double-flowered “sports”, with the stamens replaced by extra petals.

AGM cultivars

In the UK the following cultivars of Syringa vulgaris have received the Royal Horticultural Society’s Award of Garden Merit: