How do you get the lilac daffy seed in FarmVille?

You have to make the seeds in your Greenhouse. When you go to your greenhouse, you will come to a page where you have the option of selecting two different flowers (lilacs and daffodils) to make a set of lilac daffy seeds. Once you've selected the flowers necessary to make such a combination, wait three days until you can harvest them from your greenhouse. Once you've done that, go to the Market page, and find the lilac daffy seeds, click Buy then plant them on your farm!