Sunflowers are 19% crude protein, high in fat and carbs and are preferred by deer over most other options. I see no reason not to incorporate sunflowers into any mix, Spring, Summer, or Fall. Plus they are darn cheap. I buy mine at the hardware store in bulk.
I'm really surprised no one has come out with a Buck on the Bag sunflower Super Spring mix marketed to food plotting deer hunters. Biologic is missing the boat !