I really don't remember the plot, but she has the flower power something like that, and the power was supposed to be his older brother, and his older brother and father have red hair, and a stepsister with blonde hair.
This is Solitary Lady, aka Untouchable Lady.
Noblewoman Hillis Inoaden has had many lives so far (seven, to be exact) but she has always been regarded the same in all of them: meek, submissive, and a pest. But in her eighth resurrection, she no longer bends to the nobles that encircle her, nor does she continue to live in the shadows of her wicked brother and stepsister. With a sacred power passed down from her lineage and the title of Family Head, she sets out for revenge and to change the grave destiny that awaits her.
The hereditary power in the synopsis is rose themed. Her older brother wanted to take this power for himself, but couldn't because she's the one who awakened to it.
The main character has pink hair, her brother (and father) are a darker red, the step sister is blonde.