Echinacea. Coneflower seeds - White Coneflower. One of the most popular perennials in the garden. In addition to being beautiful the flowers, with stems that can reach as high as 5 feet tall and long-lasting white flowers that are visible from afar, it is easy to see why every gardener should want them in their garden or meadow. Attracts butterflies and hummingbirds to your garden!