Native Plants

San Luis Mountain Giant Hyssop

Agastache mearnsii

USDA symbol: AGME2

perennial subshrub

Lower 48 states: native

If you’re looking for a truly special addition to your native plant garden, meet the San Luis Mountain giant hyssop (Agastache mearnsii). This perennial herb is like finding a hidden gem in the world of native plants – beautiful, beneficial, and wonderfully aromatic, but not something you’ll stumble across in ...

San Luis Mountain Giant Hyssop may be listed as rare in your area.
Global Conservation Status

Status: S3? | Vulnerable: Found only in a restricted range (even if abundant at some locations). Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals.

San Luis Mountain Giant Hyssop: A Rare New Mexican Treasure for Your Garden

If you’re looking for a truly special addition to your native plant garden, meet the San Luis Mountain giant hyssop (Agastache mearnsii). This perennial herb is like finding a hidden gem in the world of native plants – beautiful, beneficial, and wonderfully aromatic, but not something you’ll stumble across in every garden center.

What Makes This Plant Special?

San Luis Mountain giant hyssop is a forb herb, meaning it’s a non-woody perennial that comes back year after year. Don’t let the technical term fool you – this is simply a gorgeous flowering plant that belongs to the mint family, and like its cousins, it offers wonderfully fragrant foliage that releases its scent when brushed against.

The plant produces stunning purple-blue flower spikes that stand tall above the aromatic foliage, creating vertical interest in garden designs. These blooms aren’t just pretty to look at – they’re absolute magnets for pollinators, attracting bees, butterflies, and even hummingbirds to your garden.

Where Does It Come From?

This native beauty calls New Mexico home, where it naturally thrives in the mountainous regions of the state. As a plant species native to the lower 48 states, it’s perfectly adapted to North American growing conditions – specifically the challenging mountain environment of the Southwest.

  • Species observed
  • No observations

A Word About Rarity

Here’s something important to know: San Luis Mountain giant hyssop has a Global Conservation Status of S3?, which indicates its status is somewhat undefined but potentially of concern. This means if you decide to grow this special plant, please make sure you source it responsibly from reputable native plant nurseries or seed companies that don’t harvest from wild populations.

Why Your Garden Will Love It

This plant is a fantastic choice for several types of garden designs:

  • Xeriscape and drought-tolerant gardens
  • Native plant gardens showcasing regional flora
  • Pollinator gardens designed to support beneficial insects
  • Rock gardens and naturalistic landscapes

The upright growth habit and colorful flower spikes make it excellent for creating structure and vertical interest in your plantings, while its drought tolerance means less work for you once it’s established.

Growing Conditions and Care

Good news for gardeners who don’t want high-maintenance plants! San Luis Mountain giant hyssop thrives in USDA hardiness zones 5-9, making it suitable for a wide range of climates.

For best results, provide:

  • Full sun exposure
  • Well-draining soil (it won’t tolerate soggy conditions)
  • Minimal water once established – this plant loves drought conditions
  • Good air circulation to prevent any moisture-related issues

Planting and Care Tips

Spring is the ideal time to plant San Luis Mountain giant hyssop. Once you’ve found a responsibly sourced plant or seeds, choose a sunny spot with excellent drainage – think of recreating those mountain conditions it loves.

Care is refreshingly simple:

  • Water regularly during the first growing season to help establishment
  • After that, water sparingly – overwatering is more likely to cause problems than drought
  • Deadhead spent flowers to encourage continued blooming
  • In colder zones, you can cut back the stems in late fall or leave them for winter interest

The Pollinator Connection

One of the best reasons to grow this plant is its incredible value to pollinators. The nectar-rich flowers provide an important food source for native bees and butterflies, while hummingbirds are drawn to the tubular flowers. By planting San Luis Mountain giant hyssop, you’re creating a little oasis for these important garden visitors.

The Bottom Line

San Luis Mountain giant hyssop is a wonderful choice for gardeners who want to grow something truly special while supporting native ecosystems. Its combination of beauty, fragrance, low maintenance needs, and pollinator benefits makes it a standout addition to the right garden setting.

Just remember – because of its potentially vulnerable status, always source this plant responsibly. Look for nurseries that propagate their own plants rather than collecting from wild populations. By doing so, you’ll be helping to preserve this beautiful species for future generations while enjoying its unique charm in your own garden.

Agastache mearnsii is also known as...

Often we refer to plants by their common names. When shopping for plants the scientific name is the best way to positively identify the plant species you desire. But some plants have more than one name! While it doesn't happen often, nurseries might display one name while you're searching for another. Agastache mearnsii is also known as:

Agastache pallidiflora ssp. mearnsii Lint & | USDA symbol: AGPAM2

Why do some plants have more than one name? Over time plant species may be renamed for a few reasons:

  1. Botanists in different regions named the same plant without knowing it had already been classified.
  2. A species was reclassified after scientific advances in, for example, DNA analysis.
  3. Slight variations within a species are sometimes mistakenly identified as entirely new species.

Classification

Group: Dicot
Kingdom: Plantae - Plants
Subkingdom: Tracheobionta - Vascular plants
Superdivision: Spermatophyta - Seed plants
Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida - Dicotyledons
Subclass: Asteridae
Order: Lamiales
Family: Lamiaceae Martinov - Mint family
Genus: Agastache Clayton ex Gronov. - giant hyssop

Species: Agastache mearnsii Wooton & Standl. - San Luis Mountain 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