Black Rose was written by the famous Nora Roberts which is part of her In The Garden trilogy and the prequel to the book Blue Dahlia.
This is story about Rosalind Harper, the mansion she lives in, and the ghost that shares the mansion with her. Roslyn Harper is a gardener by trade, enjoying her mansion in Tennessee by making the most of a few gardening businesses. Roslyn Harper was a widow as a young woman, but made some poor decisions that led to a bad second marriage. As a result, Roselyn decided not to date or to marry again, and instead invited people into her mansion to share the beauty with her, especially her soul sisters Stella and Hayley who help in the mansion garden. Unfortunately, the Rosalind Harper mansion is also home to the Harper Bride, a lullaby-singing ghost that inhabits the Tennessee mansion as well.
Eventually, Rosalind Harper hires Dr. Mitchell Carnegie to help her figure out who this strange Harper Bride ghost is. It is at this point that Roz goes against her original vow and begins a beautiful romance with the helpful genealogist (Carnegie). Unfortunately for them, the Harper bride ghost is just not too happy about the romance, and wreaks havoc in the Tennessee mansion as a result. Regardless, the two make a commitment to each other and to "defeating" the ghost ... even though they are disparaged by attack after ghostly attack.
In conclusion, it's important to remember that we don't find out the identity of the Harper bride during this novel. Remember, it is the prequel to Blue Dahlia, which contains the actual answer to this question. This book is really more about Rosalind's and Mitchell's romance.