- You Will Get 140 Seeds Of Zinnia, Purple Prince Flower Seeds. - Watering: Medium. - Sunlight: Full Sun. - Soil pH: Neutral. - Soil pH: Neutral. - USDA Hardiness Zone (°F): 1 (< -50 °F). - Annual. - Purple. - 24-30" tall. - Full sun. - Purple prince zinnias have large showy blooms of flowers 3-5" across until frost. - Plants are bushy and have multiple flowers. - Comes with planting instructions.