Hello everyone!
I have a question I hope you can help me with. I rescued a miniature rose bush a few weeks ago from a grocery store. I put it outside and it receives really good light. I have been noticing that for some reason it’s dropping newly formed buds. Any idea what could be wrong? TIA 
My first thoughts. 1. Too much sun too soon. Did you give your rose some time to acclimate to direct sun? 2. Pot does not seem to have much drainage if any. So you might want to repot into a container with drainage.
All of what @JimBeardsley suggested, plus the pot is too small. The sun shining directly on the pot can quickly over heat it, literally cooking not only all the moisture from the soil ball but literally cooking the roots. If hot enough, long enough, it will kill the plant. A rose which is dropping newly formed flower buds is reducing its stress due to being stressed. I’d seriously bet it’s due to not being used to the hotter, brighter, harsher conditions outdoors (think of your skin after being indoors all winter, then going out in the full sun for hours on the first warm day of summer…same thing); perhaps lack of drainage in the appearing cache pot as Jim wrote; and the pot getting too hot from direct sun shining on it.
I had it on a windowsill for about a week? But took some advice and put it outside on my deck. It has been out there for awhile. Also, repotted it earlier today after this picture was taken. I’m hoping it will help. Poor baby was rootbound.
Maybe put it in a more shaded place outside you think?
