North America Native Plant

Leechleaf Delissea

Botanical name: Delissea undulata

USDA symbol: DEUN2

Life cycle: perennial

Habit: tree

Native status: Native to Hawaii  

Synonyms: Delissea argutidentata E. Wimm. (DEAR3)  âš˜  Delissea konaensis H. St. John (DEKO)  âš˜  Delissea undulata Gaudich. var. argutidentata (E. Wimm.) E. Wimm. (DEUNA)  âš˜  Delissea undulata Gaudich. ssp. undulata (DEUNU)   

Leechleaf Delissea: A Critically Endangered Hawaiian Treasure Worth Protecting If you’re passionate about native Hawaiian plants and conservation gardening, you may have heard whispers about the leechleaf delissea (Delissea undulata). This remarkable native Hawaiian tree is one of the islands’ most precious botanical treasures – and sadly, one of its ...

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) ⚘ 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

Region: United States

Leechleaf Delissea: A Critically Endangered Hawaiian Treasure Worth Protecting

If you’re passionate about native Hawaiian plants and conservation gardening, you may have heard whispers about the leechleaf delissea (Delissea undulata). This remarkable native Hawaiian tree is one of the islands’ most precious botanical treasures – and sadly, one of its most endangered.

What Makes Leechleaf Delissea Special?

The leechleaf delissea is a perennial tree that belongs to Hawaii’s native flora. As a member of the bellflower family, this species develops into a woody plant with a single trunk, typically growing greater than 13-16 feet in height under ideal conditions. However, environmental factors can sometimes result in a shorter, multi-stemmed growth form.

This plant is exclusively native to Hawaii and grows only in the Hawaiian Islands. Its distribution is extremely limited, making every individual plant incredibly valuable for the ecosystem.

A Plant in Crisis: Understanding Its Endangered Status

Here’s where things get serious, fellow plant lovers. The leechleaf delissea has a Global Conservation Status of S1, meaning it’s critically imperiled. This classification indicates there are typically 5 or fewer occurrences in the wild, with fewer than 1,000 individual plants remaining. In the United States, it’s officially listed as Endangered.

This isn’t just another rare plant – it’s a species hanging on by a thread. The extreme rarity makes it especially vulnerable to complete extinction, which is why every conservation effort matters.

Should You Plant Leechleaf Delissea?

The short answer is: only if you can source it responsibly and ethically. Given its critically endangered status, this isn’t a plant you can casually add to your garden wishlist. However, if you’re involved in conservation efforts or work with botanical institutions, growing this species can be part of important preservation work.

Growing Conditions and Care

If you do have the opportunity to grow leechleaf delissea through proper conservation channels, here’s what you need to know:

  • Climate requirements: Suited for USDA hardiness zones 10-11, requiring tropical to subtropical conditions
  • Habitat preferences: Naturally grows in mesic to wet forest environments at mid-elevations
  • Growth form: Develops as a tree with potential for both single-trunk and multi-stemmed forms
  • Longevity: As a perennial species, it’s built for the long haul when conditions are right

Alternative Native Hawaiian Plants

For most gardeners wanting to support native Hawaiian flora, consider these less endangered alternatives:

  • Other native Hawaiian bellflower family members that aren’t critically endangered
  • Native Hawaiian shrubs and trees available through ethical nurseries
  • Locally adapted native plants that support Hawaiian ecosystems

Supporting Conservation Efforts

Even if you can’t grow leechleaf delissea in your own garden, you can still help:

  • Support Hawaiian native plant conservation organizations
  • Visit botanical gardens that maintain conservation collections
  • Choose other native Hawaiian plants for your landscape
  • Spread awareness about endangered Hawaiian flora

The leechleaf delissea represents both the incredible biodiversity of Hawaii and the urgent need for plant conservation. While most of us won’t have the opportunity to grow this critically endangered species, we can all play a role in supporting the broader effort to preserve Hawaii’s unique native plant heritage. Every native plant we choose to grow – even the more common ones – helps create a network of habitat that benefits Hawaii’s entire ecosystem.

Leechleaf 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 undulata Gaudich. - leechleaf delissea

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