Syringa × chinensis Willd.
Synonyms: S. laciniata × S. vulgaris; S. dubia Pers.; S. rothomagensis Mordant de Launay; S. varina Dum.-Cours.
A deciduous bush of dense rounded habit, 10 to 15 ft high. Leaves ovate, 11⁄2 to 21⁄2 in. long, 5⁄8 to 11⁄4 in. wide, rounded or broadly wedge-shaped at the base, taper-pointed, glabrous; stalk 1⁄3 to 1⁄2 in. long. Flowers of the common lilac shade, intermediate in size between those of the common and Persian lilacs, somewhat loose; corolla tube 1⁄3 in. long, lobes 1⁄4 in. long.
A hybrid between S. laciniata and S. vulgaris, raised at Rouen in the last quarter of the 18th century by M. Varin, director of the local Botanic Garden. It was introduced to Britain about 1795. Émile Lemoine, who later repeated the cross and raised many seedlings from it, suggested that S. vulgaris was probably the seed-parent. The epithet chinensis relates to an incorrect guess at the country of origin and is quite misleading. It has, however, been cultivated in Peking for a number of years and was collected there by Joseph Hers in 1921.
The Rouen lilac is a bush of great beauty when in flower, the growths made during the summer producing the following May a pair of flower-trusses 3 to 6 in. long at each joint towards the end, so that the whole makes a heavy, arching, compound panicle. It sometimes produces fertile seed, at least on the continent.
cv. ‘Alba’. – Flowers light pink, almost white. Probably a branch-sport from the original Rouen lilac, which may have occurred in several gardens. See also S. + correlata.
cv. ‘Bicolor’. – A branch-sport of the Rouen lilac noticed by Victor Lemoine in a private garden in 1850 and put into commerce by his firm. Flowers described as slaty-grey, with a bluish violet throat.
cv. ‘Duplex’. – Flowers double. Raised by Émile Lemoine from a cross between S. laciniata (seed-parent) and a double-flowered common lilac. Put into commerce about 1897.
cv. ‘Metensis’. – Flowers rosy lilac. A branch-sport of ‘Saugeana’, which occurred on a plant growing in the Place d’Esplanade at Metz. It was propagated by Messrs Simon-Louis and distributed in 1871-2.
cv. ‘Saugeana’. – Flowers rather darker and redder than in the original form. This is said to have been named for the nurseryman Saugé, who was son-in-law of Varin, raiser of the original Rouen lilac, and to have been raised from seed, around 1809. The same, or similar, lilac was distributed by Loddiges, the Hackney nurseryman, as S. chinensis rubra.
S. + correlata A. Braun – This was described in 1873 by A. Braun from a plant growing in the Berlin Botanic Garden. He observed that the white flowers resembled those of S. vulgaris while the leaves were those of the Rouen lilac, and suggested that the plant might be the result of a back-cross between the latter and a white-flowered common lilac. It is considered by Hjelmqvist to be a periclinal chimera (graft-hybrid), whose outer tissues derive from the common lilac, the inner from the Rouen. It is not certain if the true plant is in cultivation in Britain.