|The cultivar, 'Haku Ookan' is a vigorous vine with large, violet-blue flowers with dark stamens in summertime. Perfect for growth over arbors and fences. Top of the vine should be in full sun with roots shaded and cool. Keep moist until established. Ater established water enough to keep plant moist but not wet. Fertilize in spring just before new growth begins. Some pruning of stems is necessary in spring.