- Name: Sweet Coneflower - Other Common Names: Sweet Black Eyed Susan - Scientific Name: Rudbeckia Subtomentosa - Color: Yellow Flowers With Dark Brown Centers - Plant Seeds: Outdoors After Frost / Fall / Cold Stratify / Indoors Weeks Before Last Frost - Plant Height: 60" - Plant Spacing: 24 - 36" - Bloom Time: Aug – Oct - Hardiness Zone: 3 – 8 - Light Requirements: Sun - Part Shade - Soil & Water Preferences: Average – Dry - Quantity: 300 Seeds