Hummer/butterfly garden: Showy Milkweed is a perennial, with three foot tall stems and large gray five inch leaves. One plant can form a large clump by its spreading rhizomes. It needs sun. It is quite drought tolerant,(not in the same league though as Asclepias A. eriocarpa, erosa or californica ) plant, water well first summer and ignore. Tolerates alkaline soils and most gardens. Needs cross-pollination for fruit and seed development. Pollen is self-incompatible.