Oval bluish green leaves look almost succulent and are slightly marbled when new. As they spiral up arching stems, the leaves turn themselves into blue and purple petal-like bracts that closely wrap around dangling, nectar-rich purple bell flowers. Cooler autumn nights encourage a deeper blue.
Collect the large black seeds, perhaps by bagging a whole stem, before they shoot out and are killed by the first frost. New flowers have a slight honey smell. The weight of the clustered flowers and bracts can bend the stems over too far, so some gardeners support them. Stems will be shorter in less rich soil and maximum sun.