Make your flowers by cutting petals from the balloons so that the curves contribute.
(For the Iris I made 6 petals.) Having prepared a stem of willow make a centre for the flower by binding a ruffle of paper with masking tape. I used mainly white crepe paper. For the Iris I added detail with strips of maroon tissue and some ink lines. Then bind each petal in sequence to your stem. I added leaf sepals at the base cut from the green balloon and anchored it all with blue and green tissue. I added 2 leaves to each stem wrapping it all tightly with floral tape.