North America Native Plant

Cusick’s Giant Hyssop

Botanical name: Agastache cusickii

USDA symbol: AGCU

Life cycle: perennial

Habit: subshrub

Native status: Native to the lower 48 states  

Synonyms: Agastache cusickii (Greenm.) A. Heller var. parva Cronquist (AGCUP)   

Cusick’s Giant Hyssop: A Fragrant Native Treasure for Your Garden If you’re looking for a native plant that combines stunning beauty with incredible fragrance, let me introduce you to Cusick’s giant hyssop (Agastache cusickii). This delightful perennial is like the hidden gem of the northwestern United States – not everyone ...

Rare plant alert!

Region: Conservation status by state

Status: S3S4: Status is uncertain but is somewhere between the following rankings: Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘

Cusick’s Giant Hyssop: A Fragrant Native Treasure for Your Garden

If you’re looking for a native plant that combines stunning beauty with incredible fragrance, let me introduce you to Cusick’s giant hyssop (Agastache cusickii). This delightful perennial is like the hidden gem of the northwestern United States – not everyone knows about it yet, but those who do absolutely love it!

What Makes Cusick’s Giant Hyssop Special?

Cusick’s giant hyssop is a charming forb herb that brings both visual appeal and aromatic pleasure to any garden. Picture this: dense spikes of small purple-blue flowers rising above fragrant foliage that releases a delightful scent when brushed against. It’s like having your own personal aromatherapy garden right outside your door!

This perennial beauty is native to the northwestern United States, specifically thriving in Idaho, Montana, Nevada, and Oregon. Being a true native means it’s perfectly adapted to the challenging conditions of this region – think hot, dry summers and cold winters.

Why Plant Cusick’s Giant Hyssop?

Here’s where things get exciting for both you and your local wildlife:

  • Pollinator magnet: Bees, butterflies, and hummingbirds can’t resist those nectar-rich flowers
  • Low maintenance: Once established, it’s incredibly drought tolerant
  • Fragrant foliage: The aromatic leaves add sensory appeal to your garden
  • Long blooming: Enjoy flowers from summer into fall
  • Native plant benefits: Supports local ecosystems and requires minimal resources

Important Conservation Note

Here’s something crucial to know: Cusick’s giant hyssop has a conservation status of S3S4, which means it faces some level of concern in the wild. While this makes it even more special to grow, it’s absolutely essential that you source your plants or seeds responsibly. Always purchase from reputable native plant nurseries that ethically propagate their stock rather than wild-collecting. By growing this plant responsibly, you’re actually helping with conservation efforts!

Perfect Garden Spots for This Beauty

Cusick’s giant hyssop shines in several garden settings:

  • Rock gardens: Its compact size and drought tolerance make it perfect
  • Xeriscape gardens: Thrives with minimal water once established
  • Native plant gardens: A natural choice for regional authenticity
  • Pollinator gardens: Essential for supporting local bee and butterfly populations
  • Fragrant gardens: Adds aromatic interest near seating areas or pathways

Growing Conditions and Care

The good news is that Cusick’s giant hyssop is relatively easy to please once you understand its preferences:

Sunlight: Full sun is essential – this plant loves basking in bright light all day long.

Soil: Well-draining soil is non-negotiable. It can handle poor soils but will struggle in heavy, waterlogged conditions.

Water: Drought tolerant once established, but appreciate occasional deep watering during extreme dry spells.

Climate: Hardy in USDA zones 4-8, making it suitable for areas with cold winters and warm summers.

Planting and Care Tips

Ready to add this fragrant beauty to your garden? Here’s how to set it up for success:

  • Timing: Plant in spring after the last frost date
  • Spacing: Give plants adequate room for air circulation
  • Watering: Water regularly the first year to establish roots, then reduce frequency
  • Maintenance: Deadhead spent flowers to encourage continued blooming
  • Winter prep: Leave seed heads for wildlife and cut back in early spring

The Bottom Line

Cusick’s giant hyssop is a wonderful choice for gardeners who want to support native wildlife while enjoying a beautiful, low-maintenance plant. Its combination of attractive flowers, fragrant foliage, and ecological benefits makes it a true garden treasure. Just remember to source it responsibly – this special plant deserves our conservation-minded approach to gardening.

Your garden (and local pollinators) will thank you for adding this northwestern native to your landscape!

Cusick’s Giant Hyssop

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Lamiales

Family

Lamiaceae Martinov - Mint family

Genus

Agastache Clayton ex Gronov. - giant hyssop

Species

Agastache cusickii (Greenm.) A. Heller - Cusick's giant hyssop

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA