Anyone with even a passing knowledge of plants knows that daphnes have wonderfully fragrant flowers. And because some of them - usually the most scented - flower in winter, they're the sort of must-have plants that are usually among the first planted in any new garden.
There are around 50 species of Daphne, many of which are choice garden specimens. They are widespread lot, ranging from Europe and North Africa to temperate and subtropical Asia. Most of them are evergreen or nearly so, but a few are deciduous, often flowering before the foliage expands.
The plant everyone calls daphne is Daphne odora, particularly the cultivar 'Leucantha' , which is often misspelt 'Leucanthe' . This shrub, a native of China and Japan, sells in vast numbers, mainly on the strength of its perfume, but also because it's a reasonably hardy evergreen bush. It grows to around 1.5m tall with leathery, deep green leaves up to 80mm long. From mid-winter on into spring it produces clusters of small, starry, pale pink flowers. Several flower and foliage forms are available and the variety with yellow-edged leaves, 'Variegata' (sometimes called 'Aureomarginata' ), is often hardier and easier to grow than the species.
Daphne odora can be quite particular about soil conditions and is slightly frost tender in cold winter areas. It does best in cool, moist, humus enriched, well-drained, acid soil in sun or light shade. Work in plenty of compost or similar organic matter - it's impossible to use too much - and feed regularly with liquid fertilisers and an occasional side dressing of acid fertiliser. Kept healthy, D. odora develops quickly and is attractive even without flowers, but it isn't a long-lived bush. You can expect to have to replace it at least every 8-10 years.
Because daphnes are so popular, nurseries propagate thousands of them every year. For many years the plants were nearly all cutting-raised and with repeated propagation by this method the cutting stocks declined and became badly infected with viral diseases that were transmitted to their progeny. Around fifteen years ago Daphne odora 'Leucantha' was refreshed by producing new plants by tissue culture, thereby eliminating most of the disease problems. At the time, the improved appearance of these virus-free "high-health" plants was remarkable. Although since then new batches of tissue cultured plants have been introduced, many of the original high-health daphnes were used as cutting stock and now these plants are showing viral problems. When buying 'Leucantha' try to ensure that you get a tissue cultured plant or a first or second generation cutting from cultured stock.
Several other species are similar in appearance to Daphne odora and are well worth growing as slightly different alternatives to what everyone else has. Of these, Daphne bholua and Daphne laureola are the most commonly available.
Daphne bholua occurs in both deciduous and evergreen forms, but here they all seem to behave as semi-evergreens (or semi-deciduous if you like). It is shrub up to 3m tall, sometimes rather narrow and open in habit, that like Daphne odora flowers in winter and spring. The flowers are strongly scented, white-tinged-pink and open from deep pink buds. Black fruits (drupes) follow the flowers.
First classified in 1825 but slow to enter cultivation, it is one of a group of four species known as paper daphnes because in their home range paper and ropes were made from their bark. It was first recorded in gardens in 1938, but didn't really become at all widely grown until the late 1960s to mid 70s.
Native to the eastern Himalayas, it is somewhat tougher than Daphne odora under New Zealand conditions. Though strangely, British references often rate it as slightly less hardy. Whatever the reason for its local success, just be happy to know that in most of our gardens it thrives.
Daphne bholua is difficult to raise from cuttings and although it can be grafted, seed is the best method of propagation. The seed germinates well and while the seedlings are slow to start into strong growth, they gain vigour with age and usually flower in their fourth year.