North America Native Plant

Stream-bed Cyanea

Botanical name: Cyanea habenata

USDA symbol: CYHA13

Life cycle: perennial

Habit: shrub

Native status: Native to Hawaii  

Synonyms: Delissea habenata H. St. John (DEHA6)   

Stream-bed Cyanea: A Hawaiian Plant on the Brink of Extinction If you’ve stumbled across the name stream-bed cyanea in your native plant research, you’ve discovered one of Hawaii’s most critically endangered botanical treasures. Cyanea habenata, as botanists call it, represents both the incredible diversity of Hawaiian flora and the urgent ...

Rare plant alert!

Region: Conservation status by state

Status: SH: Status is uncertain but is somewhere between the following rankings: Possibly Extinct: Known only from historical occurrences. Still some hope of rediscovery ⚘

Stream-bed Cyanea: A Hawaiian Plant on the Brink of Extinction

If you’ve stumbled across the name stream-bed cyanea in your native plant research, you’ve discovered one of Hawaii’s most critically endangered botanical treasures. Cyanea habenata, as botanists call it, represents both the incredible diversity of Hawaiian flora and the urgent conservation challenges facing island ecosystems today.

What Is Stream-bed Cyanea?

Stream-bed cyanea is a perennial shrub that’s part of the bellflower family, endemic to the Hawaiian Islands. True to its common name, this plant historically grew in stream-bed habitats across Hawaii, where it likely formed an important part of the native riparian ecosystem.

As a multi-stemmed woody plant, stream-bed cyanea typically grows less than 13-16 feet tall, with several stems arising from near the ground. Like many Hawaiian native plants, it evolved in isolation and developed unique characteristics found nowhere else on Earth.

A Plant Teetering on the Edge

Here’s where things get serious: Cyanea habenata has a Global Conservation Status of SH, which means Possibly Extirpated. In plain English, this plant is known only from historical records, and scientists aren’t even sure if any living specimens still exist in the wild. There’s still hope for rediscovery, but it’s hanging by a thread.

This conservation status is found only in Hawaii, where it once grew in stream-bed environments throughout the islands.

Why This Plant Matters (Even If You Can’t Grow It)

You might wonder why we’re talking about a plant that’s possibly extinct. Well, stream-bed cyanea represents something important: the fragility of island ecosystems and the plants we’ve already lost or nearly lost to habitat destruction, invasive species, and climate change.

Like many Hawaiian natives, this plant likely co-evolved with native birds that served as its pollinators. Its loss represents not just one species disappearing, but the unraveling of ecological relationships that took millions of years to develop.

Can You Grow Stream-bed Cyanea?

The short answer: No, not really.

Even if plant material were available (which it likely isn’t), Cyanea habenata would require:

  • Extremely specialized growing conditions mimicking Hawaiian stream-bed habitats
  • High humidity and specific soil requirements
  • Tropical conditions (USDA zones 10-12 at minimum)
  • Expert horticultural knowledge

The plant’s facultative wetland status means it can survive in both wetland and non-wetland conditions, but that doesn’t make it any easier to cultivate outside its native habitat.

What You Can Do Instead

If you’re passionate about Hawaiian native plants and live in a suitable climate, consider supporting conservation efforts or growing other native Hawaiian species that aren’t critically endangered. Many botanical gardens and conservation organizations are working tirelessly to preserve Hawaii’s unique flora.

For mainland gardeners, the story of stream-bed cyanea serves as a reminder of why native plant gardening matters. By choosing native plants in our own regions, we help preserve local ecosystems and prevent other species from following the same path toward extinction.

A Call for Hope and Action

While you probably won’t be adding stream-bed cyanea to your garden anytime soon, its story isn’t just about loss—it’s about the importance of conservation and the value of every native plant species. Sometimes the most important plants are the ones we can’t grow, because they remind us what’s at stake when we don’t protect the wild places where they belong.

Who knows? Maybe someday a botanist will rediscover this remarkable plant thriving in a remote Hawaiian stream bed. Until then, we can honor its memory by supporting native plant conservation wherever we are.

Stream-bed 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 habenata (H. St. John) Lammers - stream-bed cyanea

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