This is Asclepias asperula, also known as Spider Milkweed, and Antelope Horns. This plant likes to live in full sun where it blossoms from late Spring until early Fall. Growing a couple feet tall, it attracts all kinds of bees, birds, and butterflies. Asclepias in general are documented nectar sources for the Monarch, Orange-edged Roadside-Skipper, Dina Yellow, Carus Skipper, Eastern Tiger Swallowtail, and Falcate Metalmark butterflies. It is also the nectar source for the Clarks sphinx, and Milkweed Tussock moths. USDA Hardiness Zones 7 to 9a.