North America Native Plant

Kauai Bluegrass

Botanical name: Poa siphonoglossa

USDA symbol: POSI

Life cycle: perennial

Habit: grass

Native status: Native to Hawaii  

Kauai Bluegrass: A Rare Hawaiian Treasure That Needs Our Protection Meet Kauai bluegrass (Poa siphonoglossa), one of Hawaii’s most endangered native grasses. This isn’t your typical lawn grass – it’s a botanical treasure that exists nowhere else on Earth except the misty mountains of Kauai. If you’re passionate about native ...

Rare plant alert!

Region: United States

Status: S1: Status is uncertain but is somewhere between the following rankings: Critically Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 5 or fewer occurrences or very few remaining individuals (<1,000) ⚘ Endangered: In danger of extinction throughout all or a significant portion of its range. ⚘

Region: United States

Kauai Bluegrass: A Rare Hawaiian Treasure That Needs Our Protection

Meet Kauai bluegrass (Poa siphonoglossa), one of Hawaii’s most endangered native grasses. This isn’t your typical lawn grass – it’s a botanical treasure that exists nowhere else on Earth except the misty mountains of Kauai. If you’re passionate about native Hawaiian plants and conservation, this remarkable species deserves your attention, though growing it comes with serious responsibilities.

What Makes Kauai Bluegrass Special?

This perennial grass may look unassuming at first glance, but it’s actually a living piece of Hawaii’s natural heritage. Kauai bluegrass forms delicate tufts of fine, blue-green foliage that sways gently in the mountain breezes of its native habitat. As a member of the grass family (Poaceae), it has that characteristic grass-like appearance, but with a distinctly Hawaiian twist that sets it apart from mainland species.

Where Does It Call Home?

Kauai bluegrass is what botanists call endemic – it exists naturally only in Hawaii, specifically on the island of Kauai. You’ll find it clinging to life in the island’s high-elevation montane wetlands and bogs, where cool, misty conditions create a unique ecosystem unlike anywhere else in the world.

A Plant in Crisis

Here’s the sobering reality: Kauai bluegrass is critically endangered. It holds a Global Conservation Status of S1, meaning it’s critically imperiled with typically fewer than 5 occurrences or less than 1,000 individuals remaining. It’s officially listed as Endangered, making it one of Hawaii’s most vulnerable native plants.

This rarity status means that if you’re considering growing Kauai bluegrass, you must proceed with extreme caution and responsibility. Only obtain plants or seeds from verified conservation sources – never collect from the wild, as this could push the species closer to extinction.

Growing Conditions: Not for the Average Garden

Let’s be honest – Kauai bluegrass isn’t going to thrive in your typical backyard garden. This plant has very specific needs that mirror its native montane wetland habitat:

  • Climate: Cool, consistently moist conditions with high humidity
  • Elevation: Prefers high-elevation environments
  • Moisture: As a facultative wetland plant, it can handle both wet and moderately dry conditions, but prefers consistent moisture
  • Hardiness: Limited to tropical and subtropical zones (USDA zones 10-11)

Is This Plant Right for Your Garden?

Honestly? Probably not – and that’s okay! Unless you’re involved in professional conservation work or have the specific conditions to replicate its native habitat, Kauai bluegrass is better appreciated in its natural setting or in specialized conservation collections.

If you’re drawn to native Hawaiian grasses for your landscape, consider working with local native plant societies to find more readily available species that can thrive in cultivation while supporting conservation efforts for rarities like Kauai bluegrass.

Conservation Over Cultivation

Sometimes the best way to show our appreciation for a plant is to protect it rather than grow it. Kauai bluegrass serves as a reminder that our native flora faces real challenges, from habitat loss to climate change. Instead of trying to grow this endangered species, consider:

  • Supporting Hawaiian native plant conservation organizations
  • Learning about and growing other native Hawaiian plants that are more readily available
  • Visiting Kauai’s natural areas responsibly to observe this species in its native habitat
  • Advocating for the protection of Hawaii’s unique montane wetland ecosystems

The Bigger Picture

Kauai bluegrass represents something larger than itself – it’s a symbol of Hawaii’s unique evolutionary history and the urgent need for conservation action. While this grass may not provide showy flowers for pollinators or dramatic landscape impact, it plays an irreplaceable role in its native ecosystem.

By understanding and respecting the story of Kauai bluegrass, we become better stewards of all our native plants. Sometimes the most beautiful gardens are the wild spaces we choose to protect rather than the ones we create in our backyards.

Kauai Bluegrass

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Commelinidae

Order

Cyperales

Family

Poaceae Barnhart - Grass family

Genus

Poa L. - bluegrass

Species

Poa siphonoglossa Hack. - Kauai bluegrass

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