Ideally, plant wildflower seeds when the plants growing in the wild would shed their seeds. With paper that is impregnated with wildflower seeds, I would start the seeds in a flat of moist seed-starting medium. Once the first pair of true leaves appear, you can transplant into small individual pots or peat pots. Plant them on your sunny hillside when the seedling are well started and growing vigorously. You'll have much better luck than if you sow them directly on the hillside.