Snow Drop by Choi Kyung-ah. A Romance manga rated Older Teen, published in English by Tokyopop.

So-na finds comfort in the flowers she grows at her Snow Drop nursery, but at her widowed father's insistence she returns to high school. There she meets Hae-gi, a teen model who shares her painful past, and the two fall in love, only to find their romance tangled in buried family secrets and fierce opposition from both households. A sweeping, emotional Korean romance.