From Storm in Heaven:

In a society where money is king, the young men known as "flowers" hold a special role. In exchange for the financial support of those who have the means to patronize them, they serve their flower masters as symbols of taste, status, and wealth. Bought and sold at the whim of their masters, theirs is a precarious existence - save for the few who are lucky enough to have masters who can see the person behind the flower.

Note - Despite the magazines it was published in, there is no actual shounen-ai in Hanamatsuri. The relationships between the male characters are more along the lines of heavy subtext.

[ Roughly translated from Aki's atogaki for the book "...Well, there isn't any BL, sorry! I don't really know what 'homo' means...(laughs)" ]