So called, but actually in the Acanthus family, is this long blooming prairie native. A wide-ranging and variable plant occurring from the central U.S. to PA south to FL and TX. Named for its supposed resemblance to the petunia, this is a hardy perennial to a foot tall with many light blue flowers from June through August. A tough plant, it is drought and soil tolerant and might be planted more than it has been. HP to zone 5 at least. Pkt. $2.