Attraction flowers are used to create Butterflies in your game. There are three different types of flower that you will come across, 'size', 'region' and 'rarity' and each flower combination will give you the chance to create different butterflies. For example, to create a Paradise Phantom butterfly, you will need the following to ensure you incubate this: A 100% Small flower, 100% Rare, and a 100% Mayan Star.
Attraction flowers will spawn in your forest at random when you're harvesting Butterflies for honeydew, for purchase in the shop, sometimes inside gifts from your friends, or for completing some missions. In addition you can feed fireflies to the frog to receive attraction flowers.
For info on event flowers please check the “Limited Time Events” section.