If it is for your mom, sister 또는 grandma maybe. The 꽃 are a nice touch, but I will tell 당신 from experience that they want to hear the words too-"I was wrong for _______. I did not mean to hurt you. I care about you. I apologise." So however 당신 say it, in a card 또는 with something, I hope 당신 will make sure to tell them, too.
