65-70 Days to maturity. Helianthus annuus. Organic Black Russian Sunflower Seeds. Non-GMO. Open Pollinated. Ornamental. Annual. Heirloom. The Black Russian sunflower is striking and grows up to 12 feet tall and is topped with massive 15-18 inch diameter flower heads. The petals are a classic yellow around solid black centers filled with edible seeds. Approximately 400 seeds/ounce.