|P. rockii 'Rock's Variety' is a deciduous shrub that grows to 7 feet high. Stems are hairless and weak, at times unable to support the weight of the flowers. Leaves with lateral leaflets are egg-shaped, toothed, to 3-1/2 inches long. Pale-lilac buds open to pure white flowers with deep purple flares and red at the base in the spring. This plant has achieved a status as a collector's plant and is, at times short in supply.