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Content Detail

Thread-leaved giant-hyssop is a striking, hardy perennial with slender, branched, gray-green foliage and rosy-orange tubular flowers.

  • Family (English) Mint
  • Family (botanic) Labaceae
  • Tree or plant type Perennial
  • Native locale North America
  • Size range Large plant (more than 24 inches)
  • Light exposure Full sun (6 hrs direct light daily)
  • Hardiness zones Zone 5 (Northern Illinois), Zone 6 (City of Chicago), Zone 7, Zone 8
  • Soil preference Moist, well-drained soil
  • Tolerances Alkaline soil, Occasional drought
  • Season of interest midsummer, late summer, early fall
  • Flower color and fragrance Fragrant, Blue
  • Shape or form Multi-stemmed, Upright
  • Growth rate Moderate

Size:

Thread-leaved giant-hyssop is a clump-forming perennial with an upright form, growing 2 to 3 feet high and 2 feet wide.

Native geographic location and habitat: 

Found in the mountains of southwestern New Mexico to central Arizona and south into northern Mexico.

Attracts birds or pollinators: 

Butterflies, bees, hummingbirds and other pollinators are attracted to the flowers.

Leaf description: 

Thread-like, gray-green, 2 inch long linear leaves that are anise or licorice-scented.  Stems are erect and square.

Flower description: 

Tubular-shaped, burnt-orange flowers are carried on a long inflorescence.

Fruit description:

Seeds are small nutlets.

Plant care:

Thread-leaved giant-hyssop is an excellent choice for dry, sunny areas in the garden. Full sun in well-drained soil is a must. Intolerant of wet sites or high humidity. Cut back plants in spring to promote new growth.

Pests, diseases, and tolerances:

No problems of any importance.

Cultivars and related hybrids:  Hybrids are usually showier and hardier and come in a wide variety of colors. Most are 2 to 4 feet high with fragrant, licorice-scented gray-green foliage.  

Desert Sunrise hyssop (Agastache ‘Desert Sunrise’):

Orange-pink and lavender flowers grow on a plant 3 to 4 feet high and 2 feet wide.

Firebird hyssop (Agastache ‘Firebird’): 

Growing 2 to 3 feet high and 2 feet wide, this cultivar has long terminal spikes of orange-copper flowers.

Tutti-frutti giant hyssop (Agastache pallida x A. mexicana ‘Tutti-Frutti’):

At 2 1/2 feet high and 1 to 1 1/2 feet wide at maturity, this hybrid sports 6 to 10 inch terminal spikes of tubular-shaped raspberry flowers.

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