Daphnes for Pennsylvania Gardens

Daphne spp. is a genus of small, attractive shrubs with incredibly fragrant flowers. All the species are native to Asia, Europe, and North Africa. Daphnes are in the family Thymelaeaceae. Though non-native, they are not known to be invasive. In fact, it is commonly thought that they are hard to establish. Plantsman Michael Dirr says that these shrubs sometimes die very quickly for "no explicable reason." Several hybrid cultivars have been developed and are quite attractive shrubs, worthy of inclusion in many Pennsylvania gardens.

Growing Daphnes

Daphne x burkwoodii and Daphne x transatlantica are two hybrids with noteworthy cultivars that are hardy in all of Pennsylvania. Daphne x burkwoodii is a cross between D. cneorum and D. caucasica and is hardy in USDA Plant Hardiness Zones 4 to 8. Daphne x transatlantica is a cross between D. caucasica and D. collina and is hardy in USDA Plant Hardiness Zones 5 to 8. These hybrid, semi-evergreen to evergreen shrubs prefer to grow in partial shade. The foliage can suffer from winter burn, so a location protected from winter winds is ideal. They must have well-drained soils with a neutral pH. Daphnes do not like to be too dry, and benefit from both a summer mulch to keep the soil cooler and moister, and a winter mulch to retain moisture and reduce the temperature variability that leads to winter heaving.

Always plant the shrub at the same level that it was in the container. Dig the hole just as deep as, but wider than, the rootball. In areas of hard clay soil, consider a raised planting area. Daphnes are reported to be hard to establish, so provide them with the location and conditions they prefer. It is best to leave these slow-growing shrubs (their roots!) undisturbed once planted. Mulching them will also reduce the need to weed and, thus, reduce the incidence of disturbing their roots.

Daphnes do not require much maintenance except for watering during a dry spell. Ensure that this shrub does not suffer from drought. Little pruning is needed, but remove crossing or damaged stems, including stems and foliage damaged by winter burn.

Daphnes can be propagated through layering or through stem cuttings. Propagate with either softwood cuttings taken in early summer or hardwood cuttings taken in late summer. This process requires patience, as they may take up to a year to root.

Use in the Garden

Daphne's flower clusters attract pollinators such as bees and butterflies. Cultivars that bloom in spring are useful because they provide nectar and pollen when there is not much of it to be found.

The flowers are followed by small, red berries. These drupes, less than one inch in diameter, are poisonous to mammals, including humans and their pets. In fact, all parts of the plant are highly toxic. The leaves can cause blisters when rubbed on the skin. Ingesting any of the plant's parts can produce damage to the oral mucous membranes, vomiting, diarrhea, stupor, weakness, and convulsions. Wear gloves and a long-sleeve shirt when handling this shrub. Keep children and pets from ingesting this plant. Daphne is generally not consumed by deer and rabbits.

The main value of daphne is in its attractive qualities as a small shrub and the intensity and loveliness of the scent of its flowers. They are small, dense, rounded shrubs, usually growing wider than tall, varying by cultivar from 2 to 4 feet tall and 3 to 6 feet wide. The leaves are simple, alternate, long, and narrow. They can be blue to green or variegated, usually with yellow or white edges. The umbel flowers are white or pink, and 1 to 3 inches wide. Bloom time varies from spring through the summer. The flowers are showy, and their scent is outstanding. While this beautiful shrub can be planted as part of a woodland border, in a cottage garden, or as a foundation plant, make sure it is grown in a place you pass frequently so you can enjoy the scent to its fullest.

Problems

As previously noted, winter burn can be a problem with daphnes. Plants injured by winter burn are weakened and therefore more susceptible to other diseases and pests. Diseases can include botrytis, leaf spots, twig blight, canker, and crown rot. Pests can include euonymus scale, mealy bugs, and aphids.

Choice Cultivars

• Daphne x burkwoodii 'Briggs Moonlight' is much brighter in the landscape than 'Carol Mackie', in that its leaves have cream to yellow centers with green margins. It grows 2 to 4 feet tall. Pink flowers are plentiful.
• Daphne x burkwoodii 'Carol Mackie' is noted for its variegated foliage. It grows 2 to 3 feet tall and 3 to 4 feet wide. Light pink clusters of flowers appear in the spring. It is perhaps the most popular cultivar.
• Daphne x burkwoodii 'Silveredge' is similar in appearance to 'Carol Mackie', except it is somewhat larger and more upright.
• Daphne x transatlantica 'BLAFRA' is known in the trade as Eternal Fragrance. While its main bloom is in the spring, it will continue to bloom throughout the summer into fall. Its foliage is solid green, and the plant grows 2- to 3-feet tall and wide.
• Daphne x transatlantica 'Jim's Pride' is an award-winning "Gold Medal Plant" by the Pennsylvania Horticultural Society (1990). It boasts white flowers with yellow centers that bloom from spring until fall. Its leaves are gray-green in color. It is considered finely textured, growing 3 to 4 feet tall and 3 to 6 feet wide.