- You Will Get 200+ Seeds Of Tall Blue Cornflower Bachelor Button Centaurea Cyanus Flower Seeds. - Tall Blue Cornflower Annual Flower Seeds. - 200+ Seeds. - Plant Height: 30". - Planting Depth: .1". - Plant Spacing: 12-18". - Plant In Sun. - Bloom Period: 1 Year. - Sunlight: Full Sun. - Cultivating Difficulty: Moderate. - Watering: Medium.