I can't remember where I read this story although it was online. It's in a fantasy/medieval setting and the FL is a young (I think blonde) woman who lives alone in the city as a flower shop owner. She fled her own home after suffering abuse from her family because she is her father's daughter from an affair he had with another woman. Her half sister I believe has red hair and is also abusive of her, and tricked the FL into believing that her boyfriend was cheating with said step sister.
It is when she fled that she encountered a fairy who gave her the power to grow any plant that she had previously touched.
During her life in the city, she eventually meets the prince (I have no recollection of him). Her ex boyfriend has joined the army and they meet again at some point.
There is a political background to the story with people suffering from bad crops and hunger, so she is afraid her powers might be revealed to the world, since people would harass her for the use of her powers even though they would not be sufficient to grow entire crops.
The realm's instability due to famines causes some nobles to turn against the prince and at some point she becomes entangled in this and must reveal her powers to protect the prince and his army.
