How Many Flowers Per Zinnia Plant . Zinnia flower season in india Place a small paper bag over the flower head, or cut the flower head and hang it upside down in the paper bag. 200 MIXED COLORS CALIFORNIA GIANT ZINNIA Elegans Flower Seeds eBay from www.ebay.com Find a sunny spot in your garden for your zinnias. Deadhead spent zinnia blossoms to keep the flowers coming. Many plants labeled as annuals are actually perennials that are only hardy in the warmest hardiness zones, but zinnias will be annuals everywhere.