Despite not resembling bells in appearance, balloon flowers (Platycodon grandiflorus) are clump-forming perennials that belong to the bellflower family of plants that are easy to grow. Instead, the 2- to 3-inch star-shaped flowers are produced by swollen, balloon-like buds. This easy-to-grow variety has vivid blue-violet blooms that last all summer, but some cultivars have pink […]