Common lilac

Botanical data

Family

Oleaceae (Oleaceae)

Height

2–6 m

Width

1.5–4 m

Habit

Upright

Growth rate

Moderate

Position

Full sun

Soil

Loamy, Humus-rich, Chalky

pH reaction

pH 6.5–7.5

Moisture

Moderate

Bloom

May–June

Hardiness

USDA 3a–7b

Propagation

By layering, From cuttings

Characteristics

A large shrub or small tree with heart-shaped leaves and showy, conical panicles of small, tubular, strongly scented flowers in shades of purple, white and pink. It grows multi-stemmed and upright, reaching 2–6 m in height and 1.5–4 m in width; with age it becomes bare at the base and takes on a form close to that of a small tree. The leaves are opposite and entire, from a few to over ten centimetres long, green; they open early, several weeks before flowering — the lilac is among the first shrubs to come into leaf in spring. The bark of older trunks is greyish-brown and peels away in lengthwise strips. The inflorescence is a dense, conical panicle from about fifteen to more than twenty centimetres long, made up of small flowers with a tubular, four-lobed corolla; cultivars are divided into single- and double-flowered. After flowering, dry brown seed capsules form and persist on the shrub into winter; they have no ornamental value. It differs from the black elder (Sambucus nigra) in its leaves: simple and heart-shaped in the lilac, pinnately compound in the elder. It grows at a moderate rate and can live for as much as a hundred years. For abundant flowering it needs at least about six hours of direct sun a day; with less light it grows healthily but sets few flower buds. It does best on free-draining, humus-rich soil with a neutral to alkaline reaction (pH 6.5–7.5), but tolerates waterlogging poorly. It is exceptionally frost-hardy (USDA zones 3a–7b) and older specimens cope well with drought; in regions with mild, warm winters it flowers less freely, because it needs a distinct cold period to set buds.

Popular cultivars

‘Madame Lemoine’

A classic French cultivar from the Lemoine nursery (1890), with pure white, double flowers in dense panicles. It grows to about 4 m. The most widely planted white lilac cultivar, also valued as a cut flower.

‘Andenken an Ludwig Späth’

A German cultivar from the Späth nursery (1883), with single, dark purple flowers borne in narrow, elongated panicles. One of the darkest and longest-cultivated cultivars; it grows to about 4 m.

‘Charles Joly’

A Lemoine cultivar (1896) with double, dark purple flowers with a silvery reverse to the petals. It comes into flower later than most cultivars and so extends the flowering season; strongly fragrant.

‘Katherine Havemeyer’

A Lemoine cultivar (1922) with large, double flowers in a lavender-lilac tone that fade to pink with time, borne in very dense panicles. Valued for its intense scent and abundant flowering.

‘Krasavitsa Moskvy’

A Russian cultivar raised by Leonid Kolesnikov (introduced around 1947), also sold as Beauty of Moscow. Pink-lilac buds open into double, pearly white flowers. Regarded as one of the most striking lilac cultivars.

‘Sensation’

A Dutch cultivar from 1938 with single, purple flowers with a distinct white margin to the petals — a two-tone pattern rare among lilacs. It can be unstable: individual shoots may flower uniformly purple.

Growing and care

Companion plants

The evidence level indicates whether the relationship is backed by research, observation, or gardening tradition.

Diseases and pests

Toxicity

History and origin

The lilac reached western European gardens from the Ottoman Empire in the 16th century and quickly became one of the most beloved ornamental shrubs. Its scent has inspired many cultivars and works of culture. In the wild it grows on rocky, often limestone slopes in the mountains of the Balkan Peninsula — hence its liking for alkaline soils and its good drought tolerance. It came to western Europe by way of Vienna: it was brought from Constantinople by the imperial envoy Ogier Ghiselin de Busbecq in the 1560s and described by the Flemish botanist Carolus Clusius. In the 17th century it travelled with settlers to North America, where to this day it is one of the emblems of New England rural architecture. The breakthrough in breeding came with the work of Victor Lemoine's French nursery in Nancy, which from the 1870s to the mid-20th century introduced more than two hundred cultivars — still known as French lilacs and still forming the backbone of the commercial range. Work on new cultivars was continued by, among others, the German Späth nursery and the Russian breeder Leonid Kolesnikov. In Poland the lilac has for generations grown beside country houses, wayside shrines and cemeteries, and its colloquial name “bez” has become fixed in songs and literature.

Uses

For gardens as a specimen or in groups, for flowering informal hedges and as a cut flower. A classic feature of cottage gardens. The position should be sunny and well ventilated; the shrubs are planted in September–October or in early spring, 2–3.5 m apart and away from paving and the edges of hard surfaces — root suckers can push up through the joints, and right against a wall they are hard to cut out. It tolerates urban conditions well, which makes it useful both in home plantings and in municipal greenery. For an informal hedge it is planted in a row and pruning is limited to removing the spent panicles — shearing it to shape leaves it without flowers. With age the shrub becomes bare at the base; the base can be underplanted with ground-cover perennials that tolerate partial shade, or the lilac can be trained as a standard on a single stem. It combines well with plants of similar soil requirements — peonies, bearded irises and spring bulbs; these are planted on the south side, out of the reach of the shade cast by the grown shrub, since all of them need full sun. The lilac should not, however, be planted next to rhododendrons and other acid-loving plants. The flowers are visited in numbers by butterflies and bumblebees — the long corolla tube means the nectar is most easily reached by insects with long mouthparts; the shrub works well in plantings for pollinators. For cutting, the panicles are taken in the morning, when part of the flowers in the head have opened; removing the leaves and splitting the woody ends of the stems noticeably extends the life of the bouquet.

Trivia

• The Polish common name „bez“ is misleading — the lilac (Syringa) belongs to a different genus than the black elder (Sambucus).
• Lilac flowers are edible and are sometimes used to decorate and flavour baked goods and syrups.
• The genus name Syringa comes from the Greek syrinx — a pipe — and refers to the shoots, which are hollow inside and easy to bore out. The same name was once given to mock orange (Philadelphus), and it is to that shrub that most of the old accounts of making pipes and simple wind instruments from such shoots are attributed.
• The lilac is the official flower of the US state of New Hampshire; the shrubs planted around 1750 at the Wentworth-Coolidge Mansion in Portsmouth are still alive today — more than two and a half centuries, which is a good illustration of the species' longevity.

Frequently asked questions