Purple Coneflower. The pretty green rosette of lance shaped leaves give rise to numerous Rich, magenta, purple daisies with characteristic luminescent centers that appear from July to September. This species is by far the easiest to grow and is very tolerant of varied growing conditions. Echinacea is most popular for increasing bodily resistance to infection by strengthening the immune system. The root, leaf, flower and seeds are all highly medicinal. Beautiful plant, well loved by bees and many other pollinators. Echinacea likes full sun, plenty of water and a more alkaline type soil. Perennial Hardy to zone 3.