Zinnia Zahara Raspberry Lemonade Mix Flower Seeds - Zinnia Seeds - 50 Seeds - Qualityseeds4less Exclusive USDA Hardiness Zones: 3, 4, 5, 6, 7, 8, 9, 10 Soil type: Any, Sandy, Loamy Bloom time: Summer Zinnias are one of the easiest annuals to grow, grow quickly, and bloom heavily. They make a massive burst of color in your garden. Zinnias have bright, solitary, daisy-like flowerheads on a single, erect stem. The most common zinnia is "dahlia-flowered" and grows up to three feet. Other types are "cactus-flowered."