Boxwoods and Cold Temperatures

Boxwood & Cold Injury

Boxwoods can face troubles when they experience cold temperatures. This can lead to sections of branches dying back. We’ve also seen Volutella canker, a fungal disease that affects boxwoods and causes damage to the stems. The two issues can often be found together, with Volutella infecting stems that have been injured by the cold earlier in the season. In 2023, Purdue University noticed a higher number of boxwood samples during June and July compared to previous years. The most common diagnoses have been Volutella canker and cold damage. This year, we’ve found Joe Boggs’ observations from the Ohio State University to be similar to our own, showing the widespread concern for boxwoods.

Colletotrichum Dieback & Blight

Another problem we’re seeing more of is Colletotrichum Dieback. This issue causes stem dieback and looks similar to Volutella and winter injury. One interesting point to note is that, with all the issues mentioned, the foliage on the leaves tends to stay longer before eventually falling off. Leaf spotting and leaf drop symptoms are more suggestive of boxwood blight. While we’ve received many samples expressing concerns about boxwood blight, there have been only two confirmed landscape cases in the state. Boxwood blight can make stems look bare and create spots on the leaves.