2003 Annual and Perennial Trial Results
Plant of the Month
by Dr. Jeff Gillman, University of Minnesota
Some of the most frustrating plants that I have ever worked with, but also some of the most satisfying, are in the genus Daphne. The most common Daphne that we see here in Minnesota is Daphne x burkwoodii Carol Mackie and, while this is an attractive plant, it certainly has its share of problems. Daphne are known for their ability to get root rots at the drop of a hat and for their susceptibility to late spring frosts, but despite these problems this genus is loved for their (usually) naturally mounded form, their dense evergreen foliage, and their usually attractive, fragrant, and showy flowers.
At the TRE nursery we are looking at some new Daphne species that might have a place in Minnesota sometime in the near future, and we are also, along with Dr. Stan Hokanson, director of the University of Minnesota woody plant breeding program, trying to breed some of these plants including Daphne genkwa, Daphne caucasica, Daphne x burkwoodii, and others. By far the best plant that we have seen thus far is Daphne caucasica. This species seems to be relatively cold hardy (though we lost some plants last winter) and tolerates alkaline soils, but is definitely susceptible to late frosts.
The best part about Daphne caucasica, and the reason that it is worth putting up with its weaknesses, are its flowers. Daphne caucasica blooms from late May until October. The flowers are typically white, fragrant, and profuse. Because of its problems this plant needs breeding work, but it is possible that in a few years this shrub, or a hybrid, will be a common sight in the retail nursery yard.