Syringa vulgaris (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.^[1][2][3]

The specific epithet vulgaris means “common” – not a pejorative reference, but merely indicating that this is the most widespread lilac species.^[4]

Description

It is a large deciduous shrub or multi-stemmed small tree, growing to 6–7 m (20–23 ft) high, producing secondary shoots (“suckers”) from the base or roots, with stem diameters of up to 20 cm (8 in), which in the course of decades may produce a small clonal thicket.The bark is grey to grey-brown, smooth on young stems, longitudinally furrowed and flaking 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. The flowers have a tubular base to thecorolla 6–10 mm long with an open four-lobed apex 5–8 mm across, usually lilac to mauve, occasionally white. They are arranged in dense, terminal panicles 8–18 cm (3–7 in) long. The fruit is a dry, smooth brown capsule, 1–2 cm long, splitting in two to release the two winged seeds.^[1][6]

Garden history

Lilacs — both Syringa vulgaris and S. × persica, the finer, smaller “Persian lilac”, now considered a natural hybrid — were introduced into European gardens at the end of the sixteenth century, from Ottoman gardens, not through botanists exploring the Balkan habitats of S. vulgaris.^[7] The Holy Roman Emperor’s ambassador,Ogier Ghiselin de Busbecq, is generally credited with supplying lilac slips to Carolus Clusius, about 1562. Well-connected botanists, like the great herbalist John Gerard, soon had the rarity in their gardens: Gerard notes that he had lilacs growing “in very great plenty” in 1597, but lilacs were not mentioned by Shakespeare,^[8] and John Loudon was of the opinion that the Persian lilac had been introduced into English gardens by John Tradescant the elder.^[9] Tradescant’s Continental source for information on the lilac, and perhaps ultimately for the plants, was Pietro Andrea Mattioli, as one can tell from a unique copy of Tradescant’s plant list in his Lambeth garden, an adjunct of his Musaeum Tradescantianum; it was printed, though probably not published, in 1634: it lists Lilac Matthioli. That Tradescant’s “lilac of Mattioli’s” was a white one is shown by Elias Ashmole’s manuscript list, Trees found in Mrs Tredescants Ground when it came into my possession (1662):^[10] “Syringa alba”.

In the American colonies lilacs were introduced in the eighteenth century. Peter Collinson, F.R.S., wrote to the Pennsylvania gardener and botanist John Bartram, proposing to send him some, and remarked that John Custis of Virginia had a fine “collection”, which Ann Leighton interpreted as signifying common and Persian lilacs, in both purple and white, “the entire range of lilacs possible” at the time.

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 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.There is no fall color and the seed clusters have no aesthetic appeal.

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”.^[14] 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, whose later-developing flower-buds are better protected from late spring frosts; the Syringa x prestoniae hybrids range primarily in the pink and lavender shades.^[15]

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 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.