I really liked that you chose to add the window molding. It keeps your interest in the hydrangea. I have always been told that the left part of the frame is what draws your entry into looking at the painting/drawing, then you will roll your eyes around the subject and the right either takes you out of the picture to ‘move along’ or takes your eyes back to the subject. You really made others notice the flower and want to look at it again, before going to the next picture. This also makes judges in an art show look more closely at the picture (or that is IMHO). I really liked your picture and the highlights on the glass vase.
As for working on the leaf, I would suggest submitting it to Matt with questions you have about it. If I am fairly satisfied with what I am doing except for something I think is noticeable about the picture I rarely try to touch it up because, if you are like me, I only make it worse. As soon as I am satisfied with what I am doing I sign it and never touch it again. I doubt that others will see any need to touch it up unless you pointed it out. I did not actually see anything wrong with it; I think it is excellent.