My boys LOVE flowers, but flowers are not generally associated with boys. So it is not typically seen to have pictures of boys on layouts about them with paper flowers, or flowery designs. I am going to show you that this does not have to be the norm. It is primarily based on the paper you use, and what the pictures are about.
The first example of this is the following layout. I used a very summer/beachy/ boy type of paper (splendor). The paper works well with flowers. Then my pictures were not overly "masculine" type pictures. They are fun care free. Another key element here is that the layout is not covered in flowers, the paper flower was used entirely to accent the page, and give it a little flare.
The next layout is easy, since my boys were actually in the "flower bed" sniffing the azalea bushes. Again with this I used colors that are typical for boys, (miracle paper) and since flowers and a flow to their design I was able to use a variety of ways to accent this layout.