North America Native Plant

Kauai Delissea

Botanical name: Delissea rhytidosperma

USDA symbol: DERH2

Life cycle: perennial

Habit: shrub

Native status: Native to Hawaii  

Kauai Delissea: A Critically Endangered Hawaiian Treasure Meet the Kauai delissea (Delissea rhytidosperma), one of Hawaii’s most precious and precarious native plants. This remarkable shrub represents both the incredible botanical diversity of the Hawaiian Islands and the urgent conservation challenges facing many native species today. A Plant on the Edge ...

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

Kauai Delissea: A Critically Endangered Hawaiian Treasure

Meet the Kauai delissea (Delissea rhytidosperma), one of Hawaii’s most precious and precarious native plants. This remarkable shrub represents both the incredible botanical diversity of the Hawaiian Islands and the urgent conservation challenges facing many native species today.

A Plant on the Edge of Extinction

Critical Conservation Alert: Before we dive into the fascinating world of Kauai delissea, it’s essential to understand that this plant is critically endangered. With a Global Conservation Status of S1 (Critically Imperiled) and listed as Endangered, there are typically only 5 or fewer known populations remaining, with fewer than 1,000 individual plants in existence. This makes it one of Hawaii’s rarest native plants.

If you’re considering growing this species, please only obtain plants or seeds from reputable conservation organizations or botanical institutions with proper permits and documentation. Never collect from wild populations.

What Makes Kauai Delissea Special

The Kauai delissea is a perennial shrub that belongs to the bellflower family. True to its name, this endemic species is found only on the island of Kauai, making it a unique piece of Hawaiian natural heritage. As a multi-stemmed woody plant, it typically grows to heights of 13-16 feet, though it can sometimes reach greater heights depending on growing conditions.

Where in the World?

This rare beauty calls only one place home: the Hawaiian island of Kauai. Its extremely limited geographic distribution contributes significantly to its endangered status, as any environmental changes or habitat loss on Kauai directly impacts the entire global population of this species.

Growing Conditions and Care

Given its Hawaiian origins, Kauai delissea thrives in tropical conditions equivalent to USDA hardiness zones 10-11. While specific growing requirements for this rare species aren’t extensively documented, we can infer from its native habitat that it likely prefers:

  • Warm, tropical temperatures year-round
  • High humidity levels
  • Well-draining soil
  • Partial shade conditions, similar to forest understory environments
  • Protection from strong winds

A Plant for Conservation Gardens

Due to its critically endangered status, Kauai delissea isn’t suitable for typical home landscaping. Instead, it belongs in specialized settings such as:

  • Botanical gardens with conservation programs
  • Native Hawaiian plant collections
  • Educational institutions studying Hawaiian flora
  • Restoration projects on Kauai

Supporting Hawaiian Native Plants

While most gardeners won’t be able to grow Kauai delissea due to its rarity and specialized needs, there are other ways to support Hawaiian native plant conservation:

  • Choose other native Hawaiian plants that are more readily available
  • Support organizations working to conserve Hawaiian flora
  • Visit botanical gardens that maintain conservation collections
  • Learn about and advocate for habitat protection in Hawaii

The Bigger Picture

The story of Kauai delissea serves as a powerful reminder of the importance of plant conservation. This shrub represents thousands of years of evolution in isolation, developing unique characteristics found nowhere else on Earth. Its current endangered status highlights the fragility of island ecosystems and the urgent need for conservation efforts.

While you might not be able to add this particular plant to your garden, understanding and appreciating rare species like Kauai delissea can inspire us all to make more thoughtful choices about the plants we do grow, favoring native species that support local ecosystems and wildlife.

Every plant has a story, but some stories are more precious because they might not have many more chapters left to write. The Kauai delissea is one of those stories – a reminder of what we stand to lose and what we must work to protect.

Kauai Delissea

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

Delissea Gaudich. - delissea

Species

Delissea rhytidosperma H. Mann - Kauai delissea

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