54 - 70 days. Annual Swizzle Series Zinnia flower seeds in your garden are sure to turn heads this summer. Swizzle Series seeds grow compact short dwarfed Zinnias boasting huge, semi-doubled 4" blooms. Swizzle Series Zinnia seeds have been adapted by Kansas State University to endure the demanding prairie climate and maximize flower production while still dazzling with its beauty. Swizzle Series Zinnia flowers are easy to grow from seed and an ideal novelty for gardens prone to heat and drought across the American southwest. 100 Seeds.