The biology of Canadian weeds: 156. Daphne laureola L.

Abstract

Daphne (Daphne laureola L.) is a perennial evergreen shrub native to Eurasia and northern Africa. Introduced to North America as an ornamental shrub, the plant has readily absconded gardens and can now be found throughout suitable habitats on both the east and west coasts of the continent. In Canada, daphne has naturalized in southwestern British Columbia including Vancouver, southern Vancouver Island, and the Gulf Islands. Daphne is of particular concern to the endangered Garry oak (Quercus garryana Douglas ex Hook.) because it invades shady woodland areas, forming dense mono-specific stands that can suppress and inhibit native vegetation. The berries and all other parts of the daphne plant contain a mixture of toxic chemicals that can be fatal to humans or animals if ingested. Removal teams suggest using gloves for elimination and handling of daphne because of its corrosive sap and oil. Widespread planting combined with a lack of public knowledge regarding the species’ invasiveness has created great concern over its potential to spread. Various methods of control (chemical, manual, and biological) have been developed. The most commonly applied approach in Canada is manual control, but care must be taken to avoid contact with skin and follow-up monitoring and control is advised. A promising biocontrol agent is the fungus Phomopsis sp. denovo, which has been observed to cause high levels of mortality in D. laureola under both laboratory and field conditions.