North America Native Plant

Hawai’i Quillwort

Botanical name: Isoetes hawaiiensis

USDA symbol: ISHA5

Life cycle: perennial

Habit: grass

Native status: Native to Hawaii  

Hawai’i Quillwort: A Rare Hawaiian Treasure Worth Protecting Meet the Hawai’i quillwort (Isoetes hawaiiensis), one of Hawaii’s most endangered and specialized native plants. This isn’t your typical garden plant – in fact, it’s definitely not something you’d want to try growing in your backyard. But understanding this remarkable little survivor ...

Rare plant alert!

Region: Conservation status by state

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) ⚘

Hawai’i Quillwort: A Rare Hawaiian Treasure Worth Protecting

Meet the Hawai’i quillwort (Isoetes hawaiiensis), one of Hawaii’s most endangered and specialized native plants. This isn’t your typical garden plant – in fact, it’s definitely not something you’d want to try growing in your backyard. But understanding this remarkable little survivor can deepen our appreciation for Hawaii’s unique ecosystems and the urgent need for conservation.

What Exactly Is a Quillwort?

Don’t let the name fool you – quillworts aren’t actually related to grasses at all! The Hawai’i quillwort belongs to an ancient group of plants called lycophytes, making it more closely related to ferns than to the grasses it resembles. These perennial plants look like small tufts of grass-like leaves emerging from wetland areas, but they’re actually living fossils that have been around for hundreds of millions of years.

Instead of producing flowers and seeds like most plants we’re familiar with, quillworts reproduce using spores – much like ferns and mosses. This gives them a prehistoric charm that connects us directly to Earth’s ancient plant heritage.

Where Does It Call Home?

Isoetes hawaiiensis is found exclusively in Hawaii, making it what scientists call an endemic species. This means it evolved in isolation on the Hawaiian islands and exists nowhere else on Earth. Currently, this rare plant can only be found in Hawaii’s specialized wetland habitats.

A Plant in Crisis

Here’s where things get serious: the Hawai’i quillwort is critically imperiled, with a conservation status of S1. This designation means there are typically fewer than 1,000 individual plants remaining in the wild, often across just five or fewer locations. Every single plant matters for the survival of this species.

This rarity status is precisely why you shouldn’t attempt to grow Hawai’i quillwort in your garden – even if you could successfully recreate its specialized wetland conditions. Any collection from the wild could push this species closer to extinction.

Why This Plant Matters

As an obligate wetland species, the Hawai’i quillwort plays a crucial role in Hawaii’s aquatic ecosystems. These plants:

  • Help stabilize wetland soils with their root systems
  • Contribute to the overall biodiversity of Hawaiian wetlands
  • Serve as indicators of healthy wetland conditions
  • Represent millions of years of unique evolutionary history

Growing Conditions (For Understanding, Not Cultivation)

Understanding what the Hawai’i quillwort needs helps us appreciate why it’s so specialized and vulnerable:

  • Requires constant moisture or submersion in water
  • Thrives only in tropical conditions (USDA zones 10-11)
  • Needs specific wetland soil conditions
  • Depends on stable water levels and quality

These highly specific requirements make it virtually impossible to cultivate outside of professional conservation facilities – and extremely vulnerable to environmental changes in the wild.

How You Can Help

While you can’t and shouldn’t try to grow Hawai’i quillwort in your garden, there are meaningful ways to support its conservation:

  • Support organizations working to protect Hawaiian wetlands
  • Choose native Hawaiian plants for your landscape instead
  • Learn about and advocate for wetland conservation
  • Visit and support botanical gardens with conservation programs

Native Alternatives for Your Garden

If you’re inspired by Hawaii’s unique plant heritage, consider these native Hawaiian plants that are better suited for home cultivation:

  • Hawaiian sedges (various Carex species) for wet areas
  • Native Hawaiian grasses for ground cover
  • Hawaiian ferns for shaded, moist spots

The Hawai’i quillwort reminds us that not every native plant is meant for our gardens – some are too rare, too specialized, or too important in their natural habitats to disturb. Instead, we can honor these botanical treasures by protecting their wild homes and choosing appropriate natives for our own landscapes. Sometimes the best way to love a plant is to admire it from afar and work to ensure its survival for future generations.

Hawai’i Quillwort

Classification

Group

Quillwort

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Lycopodiophyta - Lycopods

Subdivision
Class

Lycopodiopsida

Subclass
Order

Isoetales

Family

Isoetaceae Dumort. - Quillwort family

Genus

Isoetes L. - quillwort

Species

Isoetes hawaiiensis W.C. Taylor & W.H. Wagner - Hawai'i quillwort

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