The flower petals of Tulipa clusiana ‘Tubergen’s Gem’ are pure yellow, stroked with crimson on the outside. When warmed by the sun, the flowers open wide in bright golden star-shapes. Details: eight-inches tall, blooms mid-spring, USDA zones 3-7 (pre-chill 7b-10), native to Afghanistan and Tibet. A top source for bulbs to plant this fall is Colorblends, a Connecticut-based flowerbulb wholesaler that sells direct to land care professionals and home gardeners across the country. See Colorblends.com or call 1-888-847-8637 for a printed catalog.