Trifolium incarnatum A reliably winter-hardy annual variety that does not multiply with runners (like perennial Red Clover does) and is easy to eliminate by tillage. Planted September through October, Crimson Clover forms a dense green carpet by mid-winter, fixing 125 pounds of nitrogen per acre and producing tons of humus. Does not perform well in waterlogged or acid soils. Matures in June with crimson flowers on 18 inch plants. Shade tolerant and a great summer beneficial insect attractant. Sow ¼–½ inch deep in spring, summer, or fall. Recommended seeding rate: 1-2 pounds per 1000 square feet; 30-40 pounds per acre. Pre-inoculated.