North America Native Plant

Hawai’i Bluegrass

Botanical name: Poa sandvicensis

USDA symbol: POSA2

Life cycle: perennial

Habit: grass

Native status: Native to Hawaii  

Hawai’i Bluegrass: A Rare Native Treasure Worth Protecting Meet Hawai’i bluegrass (Poa sandvicensis), one of the Hawaiian Islands’ most precious native grasses. This delicate perennial might not win any flashy flower contests, but it holds a special place in Hawaii’s natural heritage – and unfortunately, it’s hanging by a thread ...

Rare plant alert!

Region: Hawaii

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: Hawaii

Hawai’i Bluegrass: A Rare Native Treasure Worth Protecting

Meet Hawai’i bluegrass (Poa sandvicensis), one of the Hawaiian Islands’ most precious native grasses. This delicate perennial might not win any flashy flower contests, but it holds a special place in Hawaii’s natural heritage – and unfortunately, it’s hanging by a thread in the wild.

What Makes Hawai’i Bluegrass Special?

Hawai’i bluegrass is a true Hawaiian native, found nowhere else on Earth. This fine-textured grass creates subtle beauty with its narrow leaves and delicate, open seed heads that dance gracefully in the breeze. It’s the kind of plant that whispers rather than shouts, offering understated elegance to any landscape.

Where Does It Grow?

This endemic grass calls only the Hawaiian Islands home, typically thriving in the cooler, high-elevation areas on volcanic slopes and ridges. You’ll find it naturally occurring in Hawaii’s unique mountain ecosystems.

A Plant in Crisis

Here’s where things get serious: Hawai’i bluegrass is critically imperiled with a Global Conservation Status of S1 and is listed as Endangered in Hawaii. With typically 5 or fewer occurrences and very few remaining individuals (less than 1,000), every single plant matters. This rarity status means we need to be extra thoughtful about how we approach growing this species.

Should You Grow Hawai’i Bluegrass?

If you’re passionate about native Hawaiian plants and conservation, growing Hawai’i bluegrass can be incredibly rewarding. However, this comes with a big responsibility: only source plants or seeds from reputable conservation programs or licensed nurseries. Never collect from wild populations – they simply can’t spare a single plant.

This grass works beautifully for:

  • Native Hawaiian restoration projects
  • High-elevation naturalistic gardens
  • Erosion control on slopes
  • Conservation-focused landscapes
  • Educational gardens showcasing Hawaiian flora

Growing Conditions and Care

Hawai’i bluegrass isn’t your typical lawn grass – it has some specific needs that reflect its mountain origins:

  • Climate: Thrives in USDA zones 10-11, particularly in Hawaii’s cooler, high-elevation conditions
  • Sunlight: Prefers full sun to partial shade
  • Soil: Well-draining soils are essential
  • Water: Moderate moisture levels work best
  • Temperature: Cooler temperatures typical of higher elevations

Wetland Flexibility

One interesting characteristic of Hawai’i bluegrass is its facultative wetland status in Hawaii, meaning it can adapt to both wetland and non-wetland conditions. This flexibility might have helped it survive in various microclimates across the islands.

Planting and Care Tips

Growing this rare beauty requires patience and attention to detail:

  • Start with responsibly sourced seeds or plants from conservation programs
  • Mimic its native high-elevation habitat as closely as possible
  • Ensure excellent drainage to prevent root rot
  • Once established, it requires minimal maintenance
  • Allow it to go to seed to support natural reproduction
  • Avoid fertilizers and chemicals that might alter its natural growing conditions

Wildlife and Ecosystem Benefits

While Hawai’i bluegrass may not be a major pollinator magnet like flowering plants, it plays important ecological roles. As a native grass, it provides natural ground cover, helps prevent erosion, and contributes to the complex web of native Hawaiian ecosystems. It may also provide nesting materials for insects and small creatures.

The Bottom Line

Hawai’i bluegrass represents both an opportunity and a responsibility. If you choose to grow this endangered native, you’re becoming a conservation partner, helping preserve a piece of Hawaii’s unique natural heritage. Just remember: source responsibly, grow thoughtfully, and appreciate the privilege of nurturing one of Hawaii’s rarest treasures.

Every garden that successfully grows Hawai’i bluegrass becomes a small sanctuary for this endangered species. In a world where native plants face constant pressure, that’s not just gardening – it’s hope in action.

Hawai’i 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 sandvicensis (Reichart) Hitchc. - Hawai'i bluegrass

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