Culture
Reliably winter hardy to USDA Zone 7, which makes this shrub difficult to grow in the St. Louis area (USDA Zone 6a). This daphne is only winter hardy to about 10°F. If attempted in the St. Louis area, it should be sited in locations sheltered from cold winter winds and cold winter temperatures (e.g., south side of a home). It may be grown in containers which are overwintered in a greenhouse or on a cool sunporch which protects it from the coldest winter temperatures. Where winter hardy, this shrub is best grown in moist, rich, sandy-humusy, well-drained soils with a neutral pH in part shade. Avoid full sun (leaves will scorch) in hot summer climates. Plants grow well in Mediterranean-type conditions, but struggle in midwestern areas which have hot summers and cold winters. Sharp soil drainage is essential. Consider raised plantings in areas of heavy clay soils to insure good drainage. Winter root mulch is advisable. Do not allow soils to dry out. Established plants have some drought tolerance, but dry soils may reduce summer bloom. Daphnes are often slow to establish and are best left undisturbed once planted.
Noteworthy Characteristics
Daphne odora, commonly called winter daphne because of its late winter flowers, is a broadleaf evergreen shrub that is native to China and Japan. It typically grows to 3-4' tall and to 2-4' wide. It features intensely fragrant reddish-purple flowers with pale pink to white insides in terminal inflorescences. Flowers bloom in late January to March in USDA Zones 8-9, but in March-April in USDA Zone 7. Flowers are followed by red fruits in July-August, but fruits are infrequently produced on cultivated shrubs. Glossy, leathery, obovate to elliptic, dark green leaves (to 4" long).
Genus name originally used for laurel (Laurus nobilis) but later transferred to this genus. Originally, from the nymph of the same name from Greek mythology, but could come from an Indo-European word meaning odor.
Specific epithet means fragrant.
'Aureomarginata' is a variegated form featuring, as the cultivar name suggests, green leaves with yellow leaf margins. 'Aureomarginata' is also noted for having slightly better winter hardiness than the species.
Problems
Daphnes in the St. Louis area often suffer significant winter injury in severe winters, particularly if improperly planted in locations exposed to cold winter winds and full sun. Plants weakened by winter injury are more susceptible to disease problems. Potential diseases include botrytis, leaf spots, canker, twig blight, crown rot, root rot and virus. Potential insect pests include aphids, mealybugs and scale. Plants can be temperamental and unpredictable. Michael Dirr reports that daphnes sometimes die very quickly for “no explicable reason.”
Uses
Rounded evergreen shrub for borders and foundations. Specimen or groups. Plant near doors, decks or patios for maximum enjoyment of the super fragrant flowers. May be used as a hedge.