Why is Bark on Mulberry Tree Splitting

Question

I have a Mulberry tree that is probably 30 yrs old at least. I have noticed the bark is splitting in large vertical sections. Also, the leaves on the tree are not filling out this year. It appears that they have started but do not seem to be filling in as quickly as normal. It is now the end of May and the tree is still mostly bare.

Answer 1

The splitting bark is likely winter sun damage. The tree goes into dormancy, but bright winter sun on the trunk heats up the sap, causing it to expand. This cracks the bark, leaving it open to disease. Normally, you only see this in young trees, but it can happen to older trees if you have a warm winter or warm spells in the winter or if something that previously shaded the trunk in the past, such as another tree, is removed and the sun reaches areas it did not in the past. The slow leafing is likely a reaction to the stress of the cracks. Treat the tree with a fungicide, with a particular focus on the cracks. Give the tree some balanced fertilizer as well, to make sure it has everything it needs to recover. Do not seal the cracks. This can actually trap disease in the cracks, making it worse.