carol mackie daphne

(Question)

Hi! I have a Carol Mackie that has been beautiful for several years, last year we had very cold weather, stunting and even killing many of our plants and trees. This spring the C.M. looked dead. I decided to prune and found green in the branches. We live in WI and our lilacs are just beginning to bloom now. I trimmed the C.M. way back and found some root rot. Not all the plant, but several branches along the base. There is also black spots on those and other branches. Any Advice??

(Answer)

Daphne x burkwoodii ‘Carol Mackie’ is a stunning shrub, but it does have the reputation of being finicky, and many writers have described having Daphne specimens that die suddenly and for no apparent reason.  As one author (Michael Dirr, in his great book, “Manual of Woody Plants”), says, “when they decide to go it is usually with haste”. Daphne is susceptible to root rot, and also to several fungal diseases, one of which is Southern Blight, caused by the fungus Sclerotium rolfsii, which starts near the soil line and appears as a dark, discoloured area that is covered with a webbing of fungal threads. The fungus lives in soil and plant debris and overwinters unless mulch and other plant debris have been removed so that the soil is exposed to winter frost.  The website below provides a photo which may be helpful, and also describes the cultural practices that can help to keep this disease at bay:

https://www.gardeningknowhow.com/plant-problems/disease/controlling-southern-blight.htm

It is possible, though, that it is simply the weather that is the culprit, in particular heavy precipitation or snowfall that contributes to poor drainage. Root problems can be caused by wet soil conditions, allowing fungi to thrive, causing the roots to rot.  What you have done in pruning out the dead and diseased sections should help your shrub survive, if this is possible. Make sure your pruners are disinfected as you go. Spring has come late for many woody plants this year, so I hope you may find that your Daphne rallies.  It is always such a disappointment to lose such a wonderful specimen.