The Question and Answer section for A White Heron and Other Stories is a great resource to ask questions, find answers, and discuss the novel.
The wretched geranium represents Sylvia's empathy for the people she left behind in the city. It represents all the beauty they will ever know, as opposed to the life she now lives at the farm.
Which particular story are you referring to?
We can infer that Sylvia has a conscience of her own. Her affinity with nature and concern for the heron transcend any romantic draw that she might have had with the hunter.