North America Native Plant

Koolau Gap Catchfly

Botanical name: Silene degeneri

USDA symbol: SIDE5

Life cycle: perennial

Habit: subshrub

Native status: Native to Hawaii  

Koolau Gap Catchfly: A Lost Hawaiian Treasure The Koolau Gap catchfly (Silene degeneri) represents one of Hawaii’s botanical mysteries—a native Hawaiian shrub that may have already slipped away from our world forever. This perennial plant, endemic to the beautiful Hawaiian islands, serves as a sobering reminder of how quickly we ...

Rare plant alert!

Region: Conservation status by state

Status: SH: Status is uncertain but is somewhere between the following rankings: Possibly Extinct: Known only from historical occurrences. Still some hope of rediscovery ⚘

Koolau Gap Catchfly: A Lost Hawaiian Treasure

The Koolau Gap catchfly (Silene degeneri) represents one of Hawaii’s botanical mysteries—a native Hawaiian shrub that may have already slipped away from our world forever. This perennial plant, endemic to the beautiful Hawaiian islands, serves as a sobering reminder of how quickly we can lose our precious native flora.

A Plant Lost in Time

Silene degeneri holds the heartbreaking conservation status of Possibly Extirpated, meaning it’s known only from historical records with just a glimmer of hope for rediscovery. This native Hawaiian species was once part of the rich tapestry of plants that made the islands so unique, but hasn’t been definitively spotted in recent years.

Where It Once Called Home

This endemic treasure was found only in Hawaii, likely in the native forest ecosystems of the Koolau Mountains. As a true Hawaiian native, it evolved alongside the islands’ other indigenous plants and animals, playing its own special role in the local ecosystem.

What We Know About Its Character

The Koolau Gap catchfly was a perennial shrub, meaning it would have been a multi-stemmed woody plant typically reaching less than 13-16 feet in height. Like other shrubs, it would have had several stems growing from or near the ground, creating a bushy appearance that added structure to Hawaii’s native landscapes.

Why You Shouldn’t Try to Grow It

Here’s the important part for gardeners: please don’t attempt to locate or cultivate Silene degeneri. With its Possibly Extirpated status, any remaining plants (if they exist) are incredibly precious and should be left to conservation professionals. Disturbing potential habitat or attempting to collect seeds or cuttings could harm any surviving populations.

Better Choices for Your Hawaiian Garden

Instead of searching for this possibly extinct species, consider these wonderful native Hawaiian alternatives that can bring authentic island beauty to your landscape:

  • Native Hawaiian hibiscus varieties
  • Ohia lehua (Metrosideros polymorpha)
  • Mamane (Sophora chrysophylla)
  • Native Hawaiian mints in the Phyllostegia genus

A Conservation Message

The story of Silene degeneri reminds us why protecting native habitats and supporting conservation efforts matters so much. While we may have lost this particular species, we can still protect the many other native Hawaiian plants that remain. When planning your garden, choosing native species helps preserve Hawaii’s unique botanical heritage for future generations.

If you’re passionate about Hawaiian native plants, consider supporting local botanical gardens, native plant societies, and conservation organizations working to protect what remains of Hawaii’s irreplaceable flora.

Koolau Gap Catchfly

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Caryophyllidae

Order

Caryophyllales

Family

Caryophyllaceae Juss. - Pink family

Genus

Silene L. - catchfly

Species

Silene degeneri Sherff - Koolau Gap catchfly

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