North America Native Plant

Ravine Cyanea

Botanical name: Cyanea dunbariae

USDA symbol: CYDU3

Life cycle: perennial

Habit: shrub

Native status: Native to Hawaii  

Synonyms: Cyanea dunbarii Rock, orth. var. (CYDU2)   

Ravine Cyanea: A Critically Endangered Hawaiian Treasure Worth Protecting Meet the ravine cyanea (Cyanea dunbariae), one of Hawaii’s most endangered native plants that’s hanging on by a thread in the wild. This remarkable shrub isn’t just another pretty face in the garden – it’s a living piece of Hawaiian natural ...

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

Ravine Cyanea: A Critically Endangered Hawaiian Treasure Worth Protecting

Meet the ravine cyanea (Cyanea dunbariae), one of Hawaii’s most endangered native plants that’s hanging on by a thread in the wild. This remarkable shrub isn’t just another pretty face in the garden – it’s a living piece of Hawaiian natural heritage that desperately needs our help to survive.

What Makes Ravine Cyanea Special

The ravine cyanea is a stunning perennial shrub that typically grows 13 to 16 feet tall, though it can reach greater heights under ideal conditions. As a member of the bellflower family, this multi-stemmed woody plant produces the characteristic tubular flowers that make Cyanea species so distinctive. Its large, dramatic palmate leaves create an almost tropical umbrella effect that’s both beautiful and functional in its native habitat.

A Plant in Crisis

Here’s the reality check: Cyanea dunbariae is critically imperiled with a Global Conservation Status of S1, meaning there are typically only 5 or fewer populations remaining in the wild with fewer than 1,000 individual plants total. It’s also officially listed as Endangered in the United States. This isn’t just rare – this is extinction is knocking at the door rare.

Where It Calls Home

True to its name, the ravine cyanea is endemic to Hawaii, specifically found in the shadowy, humid ravines of certain Hawaiian islands, particularly Oahu. These plants have evolved to thrive in the unique microclimates of Hawaiian mesic to wet forests, where they’re naturally protected from harsh winds and direct sunlight.

Should You Grow Ravine Cyanea?

Here’s where things get complicated. While we absolutely want to encourage the cultivation of this incredible native plant, it should only be grown using responsibly sourced material from legitimate conservation programs or botanical institutions. Never collect plants or seeds from wild populations – that could literally push this species closer to extinction.

The Right Garden for Ravine Cyanea

If you’re lucky enough to obtain responsibly sourced plants, ravine cyanea works beautifully in:

  • Native Hawaiian restoration gardens
  • Botanical conservation collections
  • Shaded tropical landscapes with high humidity
  • Educational gardens focused on endangered species

Growing Conditions and Care

Ravine cyanea is definitely not a plant it and forget it kind of shrub. These plants are adapted to very specific conditions:

  • USDA Hardiness Zones: 10-12 (tropical climates only)
  • Light: Shade to partial shade – think dappled forest light
  • Moisture: Consistently moist soil, never waterlogged
  • Humidity: High humidity is essential
  • Wind protection: Must be sheltered from strong winds
  • Soil: Well-draining but moisture-retentive, rich in organic matter

Pollinator and Wildlife Benefits

In their native habitat, Cyanea species have co-evolved with native Hawaiian birds that serve as their primary pollinators. While the specific pollinator relationships for ravine cyanea need more study, supporting this plant means supporting the entire ecosystem it’s part of – including other endangered species that depend on healthy native plant communities.

The Bottom Line

Cyanea dunbariae represents both the incredible beauty of Hawaiian native flora and the urgent conservation challenges facing island ecosystems. If you have the right growing conditions and can source plants responsibly, growing ravine cyanea is more than gardening – it’s participating in species conservation. Just remember that with great botanical privilege comes great responsibility to protect these irreplaceable living treasures.

For those outside tropical zones or without access to conservation sources, consider supporting Hawaiian native plant conservation organizations or botanical gardens that are working to save species like the ravine cyanea. Sometimes the best way to help a plant is to support the experts who dedicate their lives to keeping it from disappearing forever.

Ravine Cyanea

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Campanulales

Family

Campanulaceae Juss. - Bellflower family

Genus

Cyanea Gaudich. - cyanea

Species

Cyanea dunbariae Rock - ravine cyanea

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