Echinacea purpurea. Purple Coneflowers Echinacea seeds produce plants that are long-blooming from July to October. At home as a border feature or in the vegetable garden. Bright mauve-pink petals surrounding a distinctive rich plum center cone. Sow 5mm (Â¼”) deep. May bloom in the first year if planted in early March, but itâ€™s their third year that is really spectacular. These perennial coneflowers attract hoverflies and parasitoid wasps, so theyâ€™re useful for pest control in companion plantings. Echinacea plants are sturdy and drought tolerant once established, so they are useful in xeriscaping. Plant height to 80cm (32″).