Introduced in 1894, ¡®Iceberg¡¯ quickly became the great American lettuce, prized by gardeners and farmers alike for the crisphead variety¡¯s firm, packed heads and knack for retaining freshness, flavor, and crunch. Cool-green, medium-sized heads with fringed, ruffled outer leaves have pale, silvery-white hearts. Unrivalled for crispiness. Thrives in cooler weather.