Cosmos flowers are about as easy to grow as it gets. You can find them in rich, bright shades of pink, purple, orange and red, soft pastels and even white. The flowers are only about 1 in. across, but they just keep coming. The plants are sturdy and intermingle well with other flowers. This is another eager self-seeder, but not to the point of nuisance. Different varieties will grow from 1 - 4 ft. tall. Cosmos are easy to start from seed. Direct sow them anytime after your last frost.