I like the compose/symphony metaphor you used. It's a lovely contrast to the sunflower: both natural beauty and composed beauty. "Feeding destiny" is lovely, and I appreciate how it lingers, but as you've already established the flowers as musically oriented, why should their next action be feeding? A different verb or a continuation of the original musical idea would carry the thought through to full resolution. Otherwise, it's a lovely haiku.

Good theme but I think wording could have been better.