The roses are probably considered the "top dog" because many are so rare. Also, the rose garden has been host to many influential rosarians from around the world, so it has a presence far beyond the local community.
Whoever is saying that the cemetery is not a garden, needs to check out the history of the cemetery. It was planned to be a garden/park from the very beginning.
Here's an article that talks about the Sacramento Cemetery as being a "garden cemetery" back in the 1800s and early 1900s
http://www.helpmefind.com/gard...
