Agastache rupestris

Common Name: threadleaf giant hyssop 
Type: Herbaceous perennial
Family: Lamiaceae
Native Range: Southwestern United States
Zone: 5 to 8
Height: 1.50 to 2.00 feet
Spread: 1.00 to 1.50 feet
Bloom Time: July to September
Bloom Description: Burnt orange with purplish calyxes
Sun: Full sun to part shade
Water: Dry to medium
Maintenance: Low
Suggested Use: Annual
Flower: Showy
Leaf: Fragrant
Attracts: Butterflies
Tolerate: Deer, Drought

Culture

Easily grown in average, dry to medium moisture, well-drained soils in full sun to part shade. Best in full sun. Best with medium moisture, particularly during the first year, but sharp soil drainage is essential. Plants will perform poorly and may not survive winter in hard clay soils that retain moisture. Plants tolerate heat and dry soils once established. Deadhead spent flowers to promote additional bloom. Sandy/gravelly mulches will protect plants and help to avoid onset of rot. Plants may also be grown in containers (pinch back foliage tips in spring to limit mature plant height). Take cuttings from containers in late summer for overwintering.

Noteworthy Characteristics

Agastache rupestris, commonly known as giant hyssop or threadleaf giant hyssop, is an upright, clump-forming perennial that typically grows to 2-3' tall. It is native to cool mountain slopes (5000' to 7000' elevation) in Arizona and New Mexico. Small, tubular, 2-lipped, salmon/burnt orange flowers with purplish calyxes bloom in summer (July-August) on erect salvia-like flower spikes (to 12" long) located atop strong, square stems clad with narrow, aromatic (anise scented), linear to linear-lanceolate, thread-like gray-green leaves (to 2" long). Sometimes a sporadic rebloom will occur in fall if plants are cut back in late summer after the initial flowering period.

Genus name comes from the Greek words agan meaning very much and stachys meaning an ear of wheat in reference to the flower spikes.

Specific epithet means living on a cliff.

This plant is sometimes commonly called sunset hyssop in reference to the resemblance of the flower colors to the hues of a sunset. It is also sometimes commonly called rock anise hyssop or licorice hyssop in reference to the minty-licorice-root beer aroma of the foliage of this mint family member.

Problems

No serious insect or disease problems. Crown/root rot may develop in poorly drained soils. Watch for rust, powdery mildew and leaf spots.

Garden Uses

Borders, cottage gardens, native plant gardens or butterfly gardens. Shorter stems facilitate use in rock gardens and containers.