(Quart) 'Black Knight' Butterfly Bush, Gorgeous Summer Blooming. Dark Violet Purple, Fragrant Flowers. Quart size plant shipped in plastic bag or 3" pot. 'BLACK KNIGHT' Butterfly Bush Quart Size Plant Quart Size Plant, 8-12" tall, 1-2 yr old Mature size is 6-8 ft Tall and Wide Full Sun, Hardy in zones 5-9 Attracts Pollinators including butterflies and hummingbirds.