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Purple Giant-hyssop

Agastache scrophulariifolia

Last reviewed: August 2026

Purple giant-hyssop is a tall perennial forb that blooms from July through September in moist meadows, woodland edges and thickets across the eastern and midwestern United States. It draws bees, butterflies and hummingbirds and prefers full sun to part sun with consistently moist soil.

Purple Giant-hyssop (Agastache scrophulariifolia)
Photo: USDA NRCS / Wikimedia Commons (Public domain)

Toxicity unknown

Purple Giant-hyssop (Agastache scrophulariifolia) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.

Light

full sun

Water

medium

Size

24"–48" H × 12"–24" W

Bloom

Jul, Aug, Sep

Native to

CT, IA, IL, IN and 14 more states

Pollinators

bees, butterflies, hummingbirds

Deer

Resistant (per Prairie Moon Nursery)

Before you buy

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Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 459 programs across 44 states, each with a link to the provider and the date we last checked it.

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Purple giant-hyssop is a tall native perennial that produces spikes of purple flowers from summer through fall. This upright plant attracts numerous pollinators and works well in perennial borders or naturalized areas.

Growing Purple Giant-hyssop

Grow Purple Giant-hyssop in full sun and medium water. Mature plants reach 24 to 48 inches tall and spread 12 to 24 inches wide. Expect low maintenance to keep it looking intentional in a front yard.

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In an HOA neighborhood

Purple Giant-hyssop is an HOA-friendly choice. Maintenance level: low. Tidiness: 3 out of 5.

Works well in: foundation, mid zone.

  • Height may appear too wild for formal front yards
  • Can look sparse in winter when dormant

Wildlife value

This plant is excellent for pollinators, attracting bees, butterflies, and hummingbirds with its nectar-rich purple flower spikes that bloom for three months.

Common questions

When does Purple Giant-hyssop bloom?
Purple Giant-hyssop typically flowers from July through September, producing tall spikes of small tubular blooms.
What pollinators visit Purple Giant-hyssop?
Bees, butterflies and hummingbirds regularly visit the flower spikes for nectar, making it a useful plant for pollinator gardens.
How much sun and water does Purple Giant-hyssop need?
It grows best in full sun to part sun with medium to consistently moist soil, and tolerates periodic wet conditions found near stream banks or low meadows.
What habitats suit Purple Giant-hyssop?
It is often found in moist woodland edges, thickets, meadows and stream corridors where soil stays evenly moist through the growing season.
Does Purple Giant-hyssop stay green year round?
No, it is an herbaceous perennial forb that dies back to the ground each fall and regrows from its root crown in spring.
Is Purple Giant-hyssop HOA-friendly?
Purple Giant-hyssop is generally an HOA-friendly choice in the right placement, with low maintenance.

These answers were drafted with an AI model from this plant's data. Verify care details with a local expert.

Native range data from vouchered herbarium specimen records and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

If something looks wrong

Common plant problems, and what to check first

These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.

See all plant problem guides

Ready to grow Purple Giant-hyssop? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.