North America Native Plant

Cindercone Isodendrion

Botanical name: Isodendrion hosakae

USDA symbol: ISHO2

Life cycle: perennial

Habit: shrub

Native status: Native to Hawaii  

Cindercone Isodendrion: A Critically Endangered Hawaiian Treasure Meet the cindercone isodendrion (Isodendrion hosakae), one of Hawaii’s most endangered native plants. This remarkable shrub represents both the incredible diversity of Hawaiian flora and the urgent need for plant conservation in our modern world. What Makes This Plant Special The cindercone isodendrion ...

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

Cindercone Isodendrion: A Critically Endangered Hawaiian Treasure

Meet the cindercone isodendrion (Isodendrion hosakae), one of Hawaii’s most endangered native plants. This remarkable shrub represents both the incredible diversity of Hawaiian flora and the urgent need for plant conservation in our modern world.

What Makes This Plant Special

The cindercone isodendrion is a perennial shrub that belongs to Hawaii’s unique native ecosystem. As a multi-stemmed woody plant, it typically grows to heights of 13-16 feet (4-5 meters), though it can sometimes develop as a single-stemmed specimen or grow taller depending on environmental conditions. Like many Hawaiian natives, this plant has evolved specifically for the island’s unique climate and soil conditions.

Where It Calls Home

This species is endemic to Hawaii, meaning it exists nowhere else on Earth. The cindercone isodendrion grows exclusively in the Hawaiian Islands, making it a true island treasure.

A Plant in Crisis

Here’s where the story takes a serious turn. The cindercone isodendrion has a Global Conservation Status of S1, which translates to Critically Imperiled. This classification means the species faces an extremely high risk of extinction due to its rarity and vulnerability. In fact, it’s federally listed as Endangered in the United States, with typically fewer than five known occurrences and fewer than 1,000 individual plants remaining in the wild.

Should You Plant Cindercone Isodendrion?

The short answer is: probably not, and here’s why. Due to its critically endangered status, this plant should only be cultivated through authorized conservation programs with responsibly sourced material. Attempting to grow this species without proper permits or plant material could actually harm conservation efforts.

If you’re passionate about supporting this species, consider these alternatives:

  • Support Hawaiian native plant conservation organizations
  • Choose other Hawaiian native plants that are more stable for your garden
  • Participate in volunteer restoration projects in Hawaii
  • Donate to botanical gardens working on endangered species recovery

Growing Conditions (For Conservation Programs Only)

For authorized conservation efforts, the cindercone isodendrion likely requires conditions similar to its native Hawaiian habitat. This would include:

  • USDA hardiness zones 10-12 (tropical to subtropical conditions)
  • Well-draining soils typical of Hawaiian dry forests
  • Protection from strong winds
  • Appropriate native companion plants

The Bigger Picture

While you might not be able to grow cindercone isodendrion in your backyard, learning about this species highlights the importance of native plant conservation. Hawaii has lost many of its endemic species due to habitat destruction, invasive species, and climate change. Every endangered plant like this one represents thousands of years of evolution and adaptation.

How You Can Help

Even if you can’t grow this particular plant, you can still make a difference:

  • Plant native species appropriate for your region
  • Remove invasive plants from natural areas
  • Support conservation organizations working to protect endangered plants
  • Spread awareness about the importance of plant conservation
  • Visit botanical gardens that participate in endangered species programs

The cindercone isodendrion may be too rare for most gardens, but its story serves as a powerful reminder of why every native plant matters. By choosing native plants for our landscapes and supporting conservation efforts, we can help ensure that future generations will still be able to marvel at the incredible diversity of our natural world.

Cindercone Isodendrion

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Dilleniidae

Order

Violales

Family

Violaceae Batsch - Violet family

Genus

Isodendrion A. Gray - isodendrion

Species

Isodendrion hosakae H. St. John - cindercone isodendrion

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