Perennial: Drought, cold and heat tolerant. The Empress series is quite vigorous, semi-trailing, large-flowered, long blooming, and has a good resistance to mildew. Good for containers, window boxes, hanging baskets, borders and beds. Attracts butterflies and hummingbirds. Bloom time: spring-fall. Bloom color: deep purple blue. Height: 12-16 inches. Width: 18-24 inches. Exposure: sun. Water: moderate/dry. USDA Z8-11.