15-18" x 15-18" wide, (seed propagated). The glowing orange flowers of this native wildflower are irresistible to hummingbirds, butterflies and people! This long-lived, tap-rooted plant needs a couple of growing seasons to establish its deep roots and reach mature size. Our uncommon strain of Asclepias is native to clay soils making it adaptable to a variety of clay and loam conditions; the most commonly available plants must be grown in sandy soils. Zones 4-9. Delayed Shipping Until 3/14/11