You will need a very lightweight synthetic material, I used the lining from an old bridesmaid dress. Why synthetic? So that it will melt when you singe the edges of the flower petals rather than burn. The lighter the fabric, the more it will curl when you singe around the petals. Thicker fabrics singe, but retain more of a flat shape and aren’t suitable for this type of flower. You won’t need more than 1/8 yard of fabric though, so if you’re not sure, just buy small amounts of a variety of synthetics. Once you’ve experimented a little at home, you’ll have a better idea which fabric to use in the future.