Seeds from Cynanchum laeve Honeyvine Milkweed Blue Vined Milkweed. A 10 to 15 foot vining perennial herb native to eastern and central U. S. states and Ontario, commonly twining through shrubs, fences and other supports. Sun loving vine for butterflies is hardy in zones 4 to 9b. The greenish-white petals are fringed with white hairs but the stems and wavy spear-shaped leaves are smooth. This plant is attractive to bees, butterflies and birds.