This is Asclepias stenophylla, also known as Slimleaf Milkweed. In general, milkweeds have numerous pollinators including but not limited to wasps, bees, birds, skippers, butterflies, moths, and beetles. 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 4 to 10.