Storm Cloud Lily-of-the-Cloud. Without a doubt, this is the largest flowering of any of the Agapanthus cultivars. I have actually measured flower stalks up to 6' high with a 10" flower head of extremely dark blue flowers, but 4 ft. is more of the norm. This plant will stop traffic. And to think that this "Agapanthus-on-steroids" is one of the more cold hardy cultivars, is rather overwhelming. This cultivar has leaves over 1/2" wide and the foliage remains evergreen into the upper teens. Plant in full sun and lime annually to get the best flower production. This cultivar is of garden origin, and is native to S. Africa. Unless ones soil is naturally high in calcium, liming will continue your flowering from year to year. I have had more gardeners in our area complain about Agapanthus flowering for the first year or two after planting, but then they stop. They are native to those limestone hills and mountains of S. Africa, so they appreciate a good dose of calcium, of which lime is he source.