Family: Apocynaceae Other names: Balloon Cotton Bush, Balloonplant, Cotton Bush, Narrow-leaved Cotton Bush Gomphocarpus physocarpus, commonly known as balloonplant, balloon cotton-bush, bishop's balls, nailhead, or swan plant, is a species of milkweed. The plant is native to southeast Africa, but it has been widely naturalized. It is often used as an…