Blue giant hyssop

Blue giant hyssop (Agastache foeniculum), also called anise hyssop, is an upright, clump-forming North American perennial with aromatic licorice-scented leaves. Its dense blue to purple flower spikes bloom from midsummer into fall and attract bees, butterflies, and other pollinators. ## Landscape use and size Plant it in the middle or back of a sunny perennial border, meadow, native planting, or herb garden. University sources give overlapping but not identical mature sizes: Wisconsin describes roughly 2–4 feet tall and 1–3 feet wide, while North Carolina Extension lists 3–5 feet tall. Expect variation with moisture, light, and growing conditions rather than a fixed height. It may self-seed; remove unwanted seedlings while small. ## Growing conditions Choose full sun to partial shade and well-drained soil that can range from moderately moist to dry. The [North Carolina Extension Plant Toolbox](https://plants.ces.ncsu.edu/plants/agastache-foeniculum/) reports flowering from June into late autumn and USDA zones 4a–8b. [Wisconsin Horticulture](https://hort.extension.wisc.edu/articles/anise-hyssop-agastache-foeniculum/) gives hardiness zones 3a–8b and notes that the plant is short-lived; the two references agree on well-drained sites and a long summer-to-fall flower display. The leaves and flowers are used in teas and other foods, but identify the plant correctly before harvesting. ## Maintenance Water new plants as they establish. Deadhead faded spikes if you want to encourage additional flowering; leave some seed heads for birds or remove them to limit self-sowing. Divide clumps in spring or fall if needed.