American Purple Top Rutabaga : ( 85 - 95 Days ) Heirloom The roots are nearly globe shaped, 4 to 6 inches in diameter with 20 inch tall tops. Excellent keeping variety. Very sweet flavor. Because rutabagas require 4 weeks longer to mature than turnips, they are best grown as a fall crop. American Purple Top Rutabaga has been around since the 1920s. The flesh turns an orange/yellow color when cooked.