Answer: Purple coneflowers are a perennial and will occasionally manage to bloom the first year from seed. Otherwise, they use the first year to become established and then begin blooming their second year. They seem to live between three and five years and bloom for all of them; they often self seed about the garden, too.
Off the top of my head I can't think of a coneflower that would bloom in alternate years, and I can't think of a biennial one, either.
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