- Name: Clasping Coneflower - Scientific Name: Rudbeckia Amplexicaulis - Color: Yellow With Red Centers - Plant Seeds: Outdoors After Frost / Indoors Weeks Before Last Frost - Bloom Time: June - Sept - Hardiness Zone: N/A (But Reseeds Itself Easily, So It Acts Like A Perennial In All Zones) - Plant Height: 18 - 24" - Plant Spacing: 18 - 24" - Light Requirements: Sun - Part Shade - Soil & Water Preferences: Average - Dry - Quantity: 3000 Seeds - Other: Attracts Bees, Birds, & Butterflies.