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A genus of small, beautiful, mostly fragrant-flowered shrubs, both evergreen and deciduous; with tough, flexible bark and young wood. Leaves alternate, except in D. genkwa, never toothed or divided, and with little or no stalk. Flowers very like those of a lilac, in having a tubular base, expanding at the mouth into four spreading lobes. (There is only one floral envelope, and it is usually called the ‘calyx’ or ‘perianth’.) They are produced in terminal heads or axillary clusters. Stamens eight, in two rows of four. Fruit berry-like, one-seeded. The outside of the flower is frequently hairy, the inside frosted or glistening. Most of the cultivated daphnes are European, and are usually found on limestone. A few are Asiatic. None is found in N. America, but Dirca palustris of the eastern United Sta tes is a near ally.
Whilst some of the daphnes are easy to cultivate, others are found by many growers and in many places to be difficult to establish. Most of the European species prefer a neutral soil; they also like good drainage combined with abundant moisture. A soil of good sandy loam is likely to suit the majority. In places like the Thames Valley, where there are frequently hot dry spells during the summer, small pieces of stone are useful laid over the roots to conserve moisture. The majority like abundant sunshine whilst they abhor dryness at the root. Daphne laureola and pontica grow well in semi-shaded spots. The rock garden affords an admirable site for all the dwarfer species. All or nearly all transplant badly, and should be given permanent places early.
Most of the evergreen species can be increased by cuttings taken in June or early July; D. blagayana by layering; and D. cneorum by either method. D. mezereum is propagated by seed, which should be harvested as soon as the fruits show colour and sown immediately; owing to the increasing prevalence of virus disease it is important that seed should only be taken from vigorous and healthy specimens. Any other species that produces fruit may be increased in the same way. Grafting is also resorted to, and generally D. mezereum seedlings for the deciduous ones and seedlings of D. laureola for the evergreen ones, though the former may be used for both. See further under D. petraea.
It has, however, to be admitted that many of the daphnes are still untamed wildings. In some places a few species find the conditions so suitable that they thrive without any special care. But I know of no place where the cultivation of all the daphnes, or even the hardier ones, has been satisfactorily achieved. It is quite possible also that, like many shrubs that flower with the same profusion, they are naturally short-lived.
There has been no botanical study of the genus since Keissler published his monograph on the section Daphnanthes (Bot. Jahrb., Vol. 25, 1898, pp. 29–125). For an authoritative horticultural survey see: Eliot Hodgkin in Journ. R.H.S., Vol. 86, 1961, pp. 481–488. Mr Hodgkin has provided us with useful comments and information during the preparation of this volume. An earlier study by A. M. Amsler will be found in Vol. 78, 1953, PP-5–18.
Since Volume II of the present edition was published in 1973, a work of exceptional excellence has been published by the Alpine Garden Society. This is: C. D. Brickell and B. Mathew, Daphne. The Genus in the wild and in cultivation (1976). It is copiously illustrated and devotes extensive space to the cultivation of the daphnes, as well as dealing authoritatively with the taxonomy of the cultivated species.