LadyCalico The pinks represent true childlike innocence. We had been frequently told about how Stanley's appearance of innocence, helplessness, and vulnerability attracted people to her, to come to her aid or do her bidding. After being told of the death of the little girl carrying a bouquet of pinks, Asa first envisions the innocence of the child holding her pinks but that image morphs into one of Stanley with that same bouquet crumbling in her hands. Asa is realizing that Stanley is anything but an innocent, pampered child but instead is a conniving, narcissistic user who puts on a pretense of childlike innocence as a charm to manipulate people for her own selfish ends.
Muriel Schwenck I do not think there is anything significant beyond it's poignancy. It is a common flower with a sweet scent which it would be easy and attractive for a little girl to pick. In other words,she had probably just picked a big bunch by herself to give her mother or take somewhere, making the accident all that more tragic.