insides

I actually tried looking up the blue rose for a flower meaning. So far, all I got that might make sense is "mystery". And while I figured one possible detail of roses being "possessive" and "spiteful" (given the thorns and how they snag), a thought just occurred to me. 
I remembered in ISH somewhere about her being with colors. Does this and the other ones have something to do with that. . .or am I way off? I figured there was some connection with the roses at least since I saw them in a previous one, but I dunno.