Chinese Lilac or Rouen Lilac

(Oleaceae - Olive Family)

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• Form
  • medium-sized to large-sized ornamental shrub
  • maturing at about 10' tall by 10' wide, but sometimes larger
  • upright oval growth habit in youth, becoming leggy and spreading with age
  • medium growth rate

• Culture
  • full sun to partial shade
  • best performance occurs in full sun in moist, well-drained, neutral to slightly acidic soils of average fertility, in areas with good air circulation; it is highly adaptable to poor soils, soils of various pH, drought, and pollution, but declines under the heat and high humidity of the Deep South
  • propagated by rooted stem cuttings, seeds, grafting, or from rooted suckers
  • Olive Family, with numerous potential diseases (including powdery mildew) and pests (including borers and scales), yet Chinese Lilac is usually a vigorous, relatively trouble-free shrub, except for the annual infection of powdery mildew that arrives in late August and persists until leaf drop
  • rarely available, in ball and burlap form (having been replaced in prominence by the mildew-free lilacs, and still overshadowed by the abundance of cultivars from one of its parents, namely Common Lilac)
  • as the shrub matures, it may get quite dense, spreading, and tall; to control this (and coincidentally increase air flow within the canopy and reduce the severity of powdery mildew infection), an annual thinning of the canopy interior, coupled with lateral and terminal branch containment, can be accomplished by selectively removing a few individual large stems or small branches each year at the time of flowering, snipping off segments for indoor floral display in water-filled vases, and discarding the remaining woody debris
  • basal suckers and trunk watersprouts can be removed at any time of the year to keep the shrub tidy
  • as some degree of legginess will occur with age, the use of annuals, perennials, or facer shrubs can be implemented to hide the bare basal trunks of the shrub

• Foliage
  • medium to dark green, opposite, ovate, with a long-tapering acute apex
  • upper leaf surface is glabrous and shiny, but annually infested with powdery mildew by late August or early September, turning various degrees of speckled white or solid white
  • fall color (other than white) is green to chartreuse, and ornamentally poor

• Flowers
  • purple, violet, or white, 4" to 6" long, profusely fragrant and showy, narrow pyramidal inflorescences, often arising in pairs from the terminal floral buds, flowering in early- and mid-May and lasting for one to two weeks
  • inflorescences occur mostly as single-flowering forms, with relatively few cultivars as compared to Common Lilac
  • while dead-heading will slightly improve the overall vigor and appearance of the shrub, it is usually impractical to perform except on young shrubs

• Fruits
  • Winter-persistent, brown dehiscent capsules occur on woody fruiting stalks, not ornamentally effective but a good identification feature of the genus

• Twigs
  • light brown to brown-gray, lightly lenticeled, with fairly stout stems having moderately-sized floral buds (often in pairs at the terminus of the season's growth) and smaller vegetative buds (as lateral buds on the flowering stems, or as lateral and terminal buds on portions of the shrub that are more shaded)

• Trunk
  • multitrunked, light brown, and slightly exfoliating in thin strips with maturity, becoming somewhat leggy with age, and with basal suckers having a rapid growth rate unless annually pruned away

• ID Summary
  • Chinese Lilac is intermediate in the character of its morphological features (foliage, inflorescences, leaves, stems, buds, suckers, and mature size) as compared to its parents (with Common Lilac being much more robust and upright, and Persian Lilac being more diminutive and spreading)
  • ovate leaves that taper to an acute apex, foliage which eventually gets powdery mildew, 5" long intensely fragrant, narrowly pyramidal inflorescences that are often purplish and single-flowering, stems with twin terminal floral buds in Winter, and legginess with age characterize Chinese Lilac

• Function
  • specimen shrub for borders, entranceways, large foundations, rows, group plantings, or deciduous screens

• Texture
  • medium texture in foliage and when bare
  • thick density in foliage and when bare, although somewhat leggy with age

• Assets
  • showy, fragrant inflorescences in early to mid-May

• Liabilities
  • leaves become infected with unsightly powdery mildew in late Summer and Autumn, becoming speckled or solid white and coupled with poor fall color
  • often becomes too large and spreading with age, as compared to its originally intended boundaries
  • some degree of legginess with age

• Habitat
  • zones 3 to 7
  • parents are native to Southern Europe (Common Lilac, Syringa vulgaris) and Iran [formerly Persia] (Persian Lilac, Syringa x persica)
  • some sources list Cutleaf Lilac (Syringa laciniata) as the second parent, instead of Persian Lilac

• Alternates
  • shrubs with fragrant inflorescences in late Winter (Hamamelis x intermedia, Hamamelis mollis, Hamamelis vernalis), early Spring (Corylopsis glabrescens, Viburnum x burkwoodii, Viburnum carlesii, Viburnum farreri, Viburnum x juddii), mid-Spring (Syringa meyeri, Syringa patula 'Miss Kim', Syringa x hyacinthiflora, Syringa x prestoniae, Syringa villosa, Syringa vulgaris), late Spring to early Summer(Itea virginica, Philadelphus coronarius, Philadelphus x virginalis), mid-Summer (Clethra alnifolia), and mid- to late Autumn (Hamamelis virginiana)

• Variants
  • several exist, primarily noted for their variation in floral color or double-flowers

• Translation
  • Syringa translates as "pipe", referring to the hollow stems.
  • x refers to the hybrid origin of the shrub.
  • chinensis translates as "from China", where the shrub was once thought to be native to (it actually was a serendipitous hybrid seedling found in Rouen, France).

• Purpose
  • Chinese Lilac is one of the "old-fashioned" shrubs with large, showy, fragrant inflorescences.

• Summary
  • Syringa x chinensis is known as a shrub with showy, early May, very fragrant inflorescences, but is susceptible to powdery mildew on its foliage by late Summer.