Blue Star, Storm Cloud Blue StarStorm Cloud Blue Star is an erect mounding perennial with near black stems that hold narrow willow like olive green foliage with silver veining that turns rich gold yellow in fall. Pyramidal clusters of small pale periwinkle star shaped flowers bloom at the tips of the stem in late spring into summer and can experience a rebloom. Best fall colors are in full sun and consistent moisture, but flowers last longer with afternoon shade in the South. Heat