Agastache foeniculum (blue giant hyssop; syn. Agastache anethiodora (Nutt.) Britton), commonly called anise hyssop, blue giant hyssop, Fragrant giant hyssop, or the lavender giant hyssop, is a species of perennial plant in the mint family, (Lamiaceae). This plant is native to much of north-central and northern North America, notably the Great Plains and other prairies, and can be found in areas of Canada. It is tolerant of deer and drought, and also attracts hummingbirds, butterflies, bumblebees, honeybees, carpenter bees, and night flying moths.

Anise hyssop is in the same family as hyssop (the mint family Lamiaceae), but they are not closely related. 

Anise hyssop was used medicinally by Native Americans for cough, fevers, wounds, diarrhea. The soft, anise-scented leaves are used as a seasoning, as a tea, in potpourri, and can be crumbled in salad. The purple flower spike is favored by bees who make a light fragrant honey from the nectar.