Kendrick is just trying to show the truth behind an unhealthy relationship by being raw and sharing his personal struggles between wanting an unhealthy physical relationship based off of sex, phyiscal touch and sight ("fatal attraction is common and what we have common is pain")and between keeping it real and building a relationship off of communication ("communication save relation") Throughout the song he shares his mental struggle of wanting to give in to his human nature or trying to stick it out for this girl he really likes. Because the definition of poetic justice is the fact of experiencing a fitting or deserving retribution for ones actions. And kendrick knows this so to stay accountable with himself he puts it it in a song. "But i could never right my wrongs 'less i write it down for real". The flower hes talking about is the relationship and hes asking; how can you trust it if it was grown in a dark room, basically off of the wrong foundation and intentions. And he knows so many people struggle with this so he wrote this in hopes of saving others relationships "breathe slow and you will find gold mines in these lines"