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Blue giant hyssop plants are 2-3.5' tall and smell strikingly of anise. Flower spikes are short (<6"). The calyx of the flower is tubular and blue-violet in color; the corolla is ~3/8" long, blue-violet, with an upper and lower lip between which protrude 4 stamens with blue-violet anthers and a style with a cleft tip. Similar to purple giant hyssop (Agastache scrophulariifolia) but the latter lacks the anise scent, has green rather than purple calyxes on the flowers, and the underside of the leaves is green, not white. Illinois Wildflowers website says "rare in Illinois …. known to occur in only Menard county…." (the Illinois Natural History Service adds Coles county).

Agastache

Agastache foeniculum

blue giant hyssop [Blooms: Jul-Aug]