Thanks for your message. There are several ornamental plum trees, but I’ll assume you have a Mexican Plum tree as they are common in this area. When such trees are young, they have smooth bark, but over time, the bark becomes rough and craggy. Thus, I would not be concerned about cracks in your bark as this is likely the transition phase.

It’s difficult to tell what has caused the discoloration of your leaves. It could be a nutrient deficiency such as lack of nitrogen. A soil test could identify soil nutrient issues. You could also get an onsite opinion from an ISA Certified Arbortist and all can be found at https://isatexas.com/

Hope this helps,

Rick Williams