This is Gomphocarpus physocarpus, also known as Balloon Plant, Cotton-bush, Oscar, Goose plant, bishops balls, Family jewels, and Hairy Balls. A very common synonym for this plant is Asclepias physocarpa. This is a favorite of the Monarch butterflies. The flowers are pretty but the seed pods really steal the show. They look like a sky full of balloons over a miniature landscape. So the seed pods actually become the real conversation piece. Gomphocarpus physocarpus is a larval host plant for the Malay Tiger, African Monarch, Jamaican Monarch, Dorippus Tiger, Soldier, Southern Monarch, Common Tiger, Queen, Ismare Tiger, Lesser Wanderer, and Monarch butterflies. This plant can be started early, inside the house, and grown as an annual, but it is a tender perennial in USDA Hardiness Zones 8 to 11.