I recently purchased an indoor miniature rose plant which had 20 or more...
I recently purchased an indoor miniature rose plant which had 20 or more unopened buds. None of the buds opened. Some had brown stems below the bud only to the main stem and fell off easily. Those that looked healthy developed the brown stem beneath the bud as well. The rose bush looks healthy. I purchased and brought it home on a below 0 day but covered it to the car. Two other rose plants were purchased on the same day yet they are blooming and growing normal. Is this plant sick or was it disturbed by the cold? I could not find anything like it on any web pages.
Since you recently purchased it and the others are fine, I suggest that you return the plant to the place of purchase for exchange or refund.
But, if you have grown attached to the little fellow, I suggest pruning all of the brown areas down to the healthy green stems.
Here are a few articles that discuss indoor miniature rose care. You can determine if you can improve the light, humidity, water, fertilizer, temperature, etc.