North America Native Plant

Treetrunk Cyanea

Botanical name: Cyanea copelandii haleakalaensis

USDA symbol: CYCOH2

Life cycle: perennial

Habit: vine

Native status: Native to Hawaii  

Synonyms: Cyanea haleakalaensis H. St. John (CYHA5)   

Treetrunk Cyanea: A Rare Hawaiian Treasure Worth Protecting Meet one of Hawaii’s most endangered botanical gems: the treetrunk cyanea (Cyanea copelandii haleakalaensis). This stunning native shrub represents both the incredible diversity of Hawaiian flora and the urgent need for plant conservation. If you’re passionate about rare plants and have the ...

Rare plant alert!

Region: United States

Status: S1T1: 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) ⚘ Subspecies or variety is 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

Treetrunk Cyanea: A Rare Hawaiian Treasure Worth Protecting

Meet one of Hawaii’s most endangered botanical gems: the treetrunk cyanea (Cyanea copelandii haleakalaensis). This stunning native shrub represents both the incredible diversity of Hawaiian flora and the urgent need for plant conservation. If you’re passionate about rare plants and have the right growing conditions, this species offers a unique opportunity to participate in preserving Hawaii’s natural heritage.

What Makes Treetrunk Cyanea Special?

The treetrunk cyanea is a perennial shrub that belongs to the Hawaiian lobeliad family, a group of plants that evolved uniquely in the Hawaiian Islands. Despite its common name suggesting a tree-like appearance, this species typically grows as a multi-stemmed woody shrub, usually reaching less than 13-16 feet in height. Its distinctive palm-like growth pattern and large leaves arranged in rosettes create an almost prehistoric appearance that’s sure to captivate any plant enthusiast.

A Plant on the Brink

Important Conservation Alert: The treetrunk cyanea is classified as Endangered in the United States, with a Global Conservation Status of S1T1. This means the species is critically imperiled and faces a very high risk of extinction. If you’re considering growing this plant, it’s absolutely essential to source it only from reputable conservation organizations or botanical institutions with legitimate propagation programs.

Where Does It Come From?

This remarkable shrub is endemic to Hawaii, meaning it exists nowhere else on Earth. More specifically, it’s native to the high-elevation forests of Haleakalā on the island of Maui. The plant has evolved to thrive in the cool, misty conditions of Hawaii’s cloud forests, making it quite different from the tropical plants most people associate with the islands.

Growing Conditions and Care

Growing treetrunk cyanea successfully requires recreating its native cloud forest habitat, which can be challenging outside of Hawaii. Here’s what this rare beauty needs:

  • Climate: Cool, consistently moist conditions similar to USDA zones 10-11, but with high humidity and protection from intense heat
  • Light: Bright, filtered light rather than direct sunlight
  • Soil: Well-draining, organic-rich soil that stays consistently moist but never waterlogged
  • Humidity: High humidity levels, often requiring supplemental misting or humidity trays in cultivation
  • Temperature: Cool to moderate temperatures, avoiding extreme heat or cold

Is This Plant Right for Your Garden?

Honestly, the treetrunk cyanea isn’t suitable for most home gardens. Its endangered status, specialized growing requirements, and limited availability make it more appropriate for:

  • Botanical gardens with conservation programs
  • Specialized native Hawaiian plant collections
  • Research institutions working on Hawaiian plant conservation
  • Experienced collectors in appropriate climates with access to ethically sourced plants

Supporting Conservation Efforts

While you might not be able to grow treetrunk cyanea in your backyard, you can still support its conservation. Consider donating to organizations working to protect Hawaiian native plants, visiting botanical gardens that maintain conservation collections, or learning about other native plants in your area that need protection.

If you do have the opportunity to grow this species through legitimate conservation channels, you’ll be participating in crucial efforts to prevent the extinction of one of Hawaii’s unique evolutionary treasures. Just remember: with great plants comes great responsibility!

The Bottom Line

The treetrunk cyanea represents both the wonder and fragility of island evolution. While it’s not a plant for every garden, it serves as an important reminder of why we need to protect native plant communities and support conservation efforts. Whether you ever get to see one in person or simply appreciate it from afar, this remarkable shrub deserves our respect and protection for future generations to enjoy.

Treetrunk 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 copelandii Rock - treetrunk cyanea

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