Dear Garden Expert, I have an ornamental cherry tree which is about 14 years old. It is well laid out and blooms every year. About three years ago the bark started to peel off the trunk. Under the bark, there are bugs, wood louses and a floury substance. I would be grateful for advice.
In this case, telediagnosis is not easy. My first thought was “frost damage”. In late winter when the days are warm but the nights are cold we have a great temperature drop between day and night. And this is not easy to handle for the plant tissue. The extremely different temperatures might cause frost cracks at the sun-facing side. These frost cracks vary in size and shape. Due to the cherries strong phloem tissue it is possible that you don´t see any damage but the bark is peeling off. And underneath parasites start to nest. After a while the bark will become lose. I wouldn´t take off bigger pieces of the bark as long as there is no fungal infestation below. But you can take off smaller pieces of the bark and clean the wound with a sharp garden knife. The bark wound will then heal in a couple of years. To sum it up: Bark protection with straw mats for ornamental shrubs or white wash for fruit trees is still the best way to protect your plants when nights are cold and days are sunny.