This is Asclepias verticillata, also known as whorled milkweed, eastern whorled milkweed, and horsetail milkweed. This is a great choice if you are looking for a deer resistant milkweed. As an added bonus the flowers are lightly scented. This plant likes to live in a dry soil that is located in full sun. This plant can blossom all the way into late September, after all of the other milkweed blooms are gone. Asclepias verticillata is a larval host plant for the Monarch, Queen, and Soldier 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 3 to 9