Purple Giant Hyssop (Agastache scrophulariifolia)
Purple giant hyssop (Agastache scrophulariifolia) is a tall, native mint‑family perennial of eastern North America, usually reaching four to six feet. It grows in upright clumps on square stems that may show purplish tones and light hair. The flower spikes range from one to six inches long and carry many small tubular blossoms in pale purple to lavender. Each flower has a two‑lobed upper lip, a three‑lobed lower lip, and four stamens that extend beyond the corolla. Leaves are opposite, sharply pointed, and borne on short stalks. They are up to four inches long and two inches wide, with coarsely toothed margins and short hairs on the petioles.
Purple giant hyssop favors moist, sandy or loamy soils in partial shade. It grows along woodland edges, in thickets, upland woods, and disturbed floodplain margins. Because it is sensitive to competition, it often persists where light disturbance keeps surrounding vegetation open.
Source‑title list
Flora of North America – Agastache scrophulariifolia
USDA Plants Database – Agastache scrophulariifolia
Illinois Wildflowers – Purple Giant Hyssop
Minnesota Wildflowers – Purple Giant Hyssop
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