Empire Blue Butterfly Bush Buddleja davidii 'Empire Blue' Description Blooms fragrant large blue flowers. Long stems with gray-green foliage.Bloom Period: SummerGrowth Habit: Rounded and vase-shapeMature Height: 5' to 6' (152 cm to 183 cm)Mature Spread: 4' to 5' (122 cm to 152 cm)Growth Rate: Fast More Details Sun Exposure: Full SunCold Hardiness Zone: 5Attracts butterflies and beesRabbit and deer resistantCut flowerGarden Tip: Deadhead to promote re-blooming