Q.Do weeping cherry trees lose their leaves in the winter?
Our tree, which is about 7′ tall, was planted about 18 months ago. The leaves are rolling up. There is a large bubble (2 ‘ in diameter) on the side of the trunk near the ground. The material in the bubble is transparent. Could this be a disease? Thank you.
A bubble-like shape on the tree sounds like some kind of canker; this article will tell you more about these: https://www.gardeningknowhow.com/ornamental/trees/tgen/cankers-on-trees.htm
Added to the rolled leaves, this sounds like something you should have positively identified as soon as possible, in order to begin any treatment, if one even exists. Call the nearest extension service office and describe the symptoms; they should tell you if they need to see samples, and how to bring them in. This article will help you locate an office: https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm
