Agastache, or Giant Hyssop, is a genus of 9–12 species of perennial herbs in the family Lamiaceae, native to eastern Asia (one species) and North America (the rest).
Most species are very upright, 0.5–3 m tall, with stiff, angular stems clothed in toothed-edged, lance shaped leaves ranging from 1–15 cm long and 0.5–11 cm broad depending on the species. Upright spikes of tubular, two-lipped flowers develop at the stem tips in summer. The flowers are usually white, pink, mauve, or purple, with the bracts that back the flowers being of the same or a slightly contrasting color.
They are easily grown in moist, well-drained soil and prefer a sunny position. Winter hardiness varies; the hardiest is A. foeniculum, hardy to USDA hardiness zone 1 in the north of its range; A. nepetoides, A. rugosa, A. scrophulariifolia and A. urticifolia are hardy to zones 3–5 in the northern parts of their ranges.
Propagate from seed or cuttings.
Pests and diseases
Agastache is relatively free of pests and diseases, with the exception of powdery mildew, rust, and other fungal pathogens that can affect the leaves during hot, humid weather if air circulation is poor.