North America Native Plant

Kauai Bottlebrush

Botanical name: Metrosideros waialealae var. waialealae

USDA symbol: MEWAW

Life cycle: perennial

Habit: shrub

Native status: Native to Hawaii  

Kauai Bottlebrush: A Rare Hawaiian Treasure Worth Protecting If you’re passionate about Hawaiian native plants, you’ve probably heard of bottlebrush plants, but the Kauai bottlebrush (Metrosideros waialealae var. waialealae) is something truly special. This isn’t your garden-variety bottlebrush – it’s one of Hawaii’s rarest native shrubs, found only in the ...

Rare plant alert!

Region: Conservation status by state

Status: S3T2?: Status is uncertain but is somewhere between the following rankings: Inexact rank: ⚘ Subspecies or variety is imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘ 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 ⚘

Kauai Bottlebrush: A Rare Hawaiian Treasure Worth Protecting

If you’re passionate about Hawaiian native plants, you’ve probably heard of bottlebrush plants, but the Kauai bottlebrush (Metrosideros waialealae var. waialealae) is something truly special. This isn’t your garden-variety bottlebrush – it’s one of Hawaii’s rarest native shrubs, found only in the misty heights of Kauai’s Mount Wai’ale’ale.

What Makes This Plant So Special?

The Kauai bottlebrush is a perennial shrub that’s endemic to Hawaii, meaning it exists nowhere else on Earth. As part of the Metrosideros family, it shares lineage with some of Hawaii’s most iconic native trees, but this particular variety has carved out its own unique niche in one of the world’s wettest spots.

This multi-stemmed woody plant typically grows as a shrub, usually staying under 13 to 16 feet in height. Like other shrubs, it develops several stems from near the ground, creating a bushy appearance that’s perfectly adapted to its mountain home.

Where You’ll Find It (And Where You Won’t)

Here’s where things get interesting – and a bit concerning. The Kauai bottlebrush is found only in Hawaii, and more specifically, it’s restricted to very limited areas on the island of Kauai. This extremely narrow distribution is part of what makes it so rare and precious.

The Rarity Reality Check

Before we talk about growing this beauty, we need to address the elephant in the room: this plant is incredibly rare. It carries a Global Conservation Status of S3T2?, which essentially means its conservation status is undefined but suggests significant concern. This isn’t a plant you’ll find at your local nursery, and that’s probably for the best.

If you’re dreaming of adding a Kauai bottlebrush to your garden, pump the brakes for a moment. Due to its extreme rarity, this plant should only be cultivated using responsibly sourced material – if it’s available at all. We’re talking about working with legitimate conservation organizations, botanical gardens, or certified native plant societies.

What We Don’t Know (And Why That Matters)

Here’s the thing about rare plants – there’s often a lot we don’t know about them, and the Kauai bottlebrush is no exception. Details about its specific growing conditions, propagation methods, wildlife benefits, and even its exact growing requirements remain largely unknown or undocumented.

This knowledge gap isn’t just academic curiosity – it makes conservation efforts more challenging and means that casual cultivation could inadvertently harm wild populations if not done properly.

Supporting Conservation Instead

Rather than trying to grow this rare gem in your backyard, consider these alternatives:

  • Support Hawaiian native plant conservation organizations
  • Visit botanical gardens that specialize in Hawaiian native species
  • Choose other native Hawaiian Metrosideros species that are less rare for your garden
  • Participate in habitat restoration projects if you live in Hawaii

The Bottom Line

The Kauai bottlebrush represents something precious and irreplaceable – a unique piece of Hawaii’s natural heritage that exists nowhere else on our planet. While it might be tempting to want to grow this rare beauty, the most loving thing we can do is protect its wild populations and support conservation efforts.

If you’re passionate about native Hawaiian plants, there are many other wonderful Metrosideros species and native Hawaiian plants that are more readily available and better suited for home cultivation. Save the rare ones for the conservation professionals, and let’s work together to ensure future generations can marvel at the Kauai bottlebrush in its natural mountain home.

Sometimes the best way to love a plant is to admire it from afar and work to protect the places where it naturally thrives.

Kauai Bottlebrush

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Myrtales

Family

Myrtaceae Juss. - Myrtle family

Genus

Metrosideros Banks ex Gaertn. - lehua

Species

Metrosideros waialealae (Rock) Rock - Kauai bottlebrush

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