North America Native Plant

Mann’s Cyanea

Botanical name: Cyanea mannii

USDA symbol: CYMA12

Life cycle: perennial

Habit: shrub

Native status: Native to Hawaii  

Mann’s Cyanea: A Rare Hawaiian Treasure Worth Protecting If you’re drawn to unique, exotic plants with a story to tell, Mann’s cyanea (Cyanea mannii) might catch your attention. This stunning Hawaiian native is more than just another tropical plant – it’s a living piece of Hawaii’s natural heritage that desperately ...

Rare plant alert!

Region: United States

Status: S2: Status is uncertain but is somewhere between the following rankings: 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) ⚘ Endangered: In danger of extinction throughout all or a significant portion of its range. ⚘

Region: United States

Mann’s Cyanea: A Rare Hawaiian Treasure Worth Protecting

If you’re drawn to unique, exotic plants with a story to tell, Mann’s cyanea (Cyanea mannii) might catch your attention. This stunning Hawaiian native is more than just another tropical plant – it’s a living piece of Hawaii’s natural heritage that desperately needs our help to survive.

What Makes Mann’s Cyanea Special?

Mann’s cyanea is a perennial shrub that belongs to Hawaii’s remarkable bellflower family. This multi-stemmed woody plant typically grows to heights of 13-16 feet, though it can sometimes reach even taller heights or develop a single stem depending on its growing conditions. What really sets this plant apart are its distinctive tubular flowers and large, tropical foliage that give any garden an authentic Hawaiian feel.

Where Does It Come From?

This beautiful plant is endemic to Hawaii, meaning it exists nowhere else on Earth naturally. Cyanea mannii grows exclusively in the Hawaiian Islands, where it has evolved over thousands of years to thrive in the islands’ unique wet forest environments.

A Plant in Crisis

Here’s where things get serious: Mann’s cyanea is in trouble. This species has a Global Conservation Status of S2, which means it’s imperiled due to extreme rarity. With typically only 6 to 20 occurrences remaining and fewer than 1,000 to 3,000 individual plants left in the wild, it’s officially listed as Endangered in the United States.

This rarity status means that if you’re considering growing Mann’s cyanea, you have a responsibility to source it ethically. Only obtain plants from reputable native plant nurseries that propagate from legally collected seeds or cuttings, never from wild populations.

Growing Mann’s Cyanea: Not for Beginners

Let’s be honest – this isn’t a plant for casual gardeners. Mann’s cyanea is extremely particular about its growing conditions and is only suitable for USDA hardiness zones 10-12. Here’s what this finicky beauty needs:

  • High humidity levels (think tropical rainforest conditions)
  • Filtered light or partial shade – direct sun will stress it out
  • Consistently moist, well-draining soil
  • Protection from strong winds
  • Warm temperatures year-round

Garden Role and Design Ideas

If you can provide the right conditions, Mann’s cyanea makes an exceptional specimen plant in tropical shade gardens. It works beautifully in Hawaiian native plant gardens or conservation-focused landscapes where its story can be shared with visitors. The plant’s exotic appearance and large foliage create a dramatic focal point, while its flowers add unique color and form.

Supporting Hawaiian Wildlife

One of the most compelling reasons to grow Mann’s cyanea (responsibly) is its role in supporting Hawaii’s native ecosystem. Hawaiian bellflowers like this one have co-evolved with native Hawaiian birds, particularly honeycreepers, which serve as their primary pollinators. By growing this plant, you’re helping preserve these important ecological relationships.

Care Tips for Success

If you’re committed to growing this rare beauty, here are some essential care guidelines:

  • Maintain consistent moisture without waterlogging
  • Provide humidity through misting or humidity trays
  • Use well-draining, organic-rich potting mix
  • Protect from temperature fluctuations
  • Monitor for pests, as stressed plants are more susceptible

The Bottom Line

Mann’s cyanea is a plant that commands respect. Its endangered status means it’s not a casual garden addition – it’s a conservation commitment. If you have the right climate, growing conditions, and can source plants responsibly, growing Mann’s cyanea can be a meaningful way to participate in preserving Hawaii’s unique botanical heritage.

However, if you’re looking for easier Hawaiian natives or similar tropical appeal, consider asking local native plant societies about other Hawaiian species that might be more suitable for your garden while still supporting conservation efforts. Remember, every plant we grow thoughtfully is a step toward preserving these incredible species for future generations.

Mann’s 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 mannii (Brigham) Hillebr. - Mann's cyanea

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