North America Native Plant

Kalalau Valley Starviolet

Botanical name: Hedyotis tryblium

USDA symbol: HETR6

Life cycle: perennial

Habit: vine

Native status: Native to Hawaii  

Synonyms: Kadua tryblium (D.R. Herbst & W.L. Wagner) W.L. Wagner & Lorence (KATR)   

Kalalau Valley Starviolet: A Rare Hawaiian Gem That’s Better Left Wild Meet the Kalalau Valley starviolet (Hedyotis tryblium), one of Hawaii’s most elusive native treasures. If you’ve never heard of this plant before, you’re not alone – and there’s a very good reason why it’s not gracing gardens across the ...

Rare plant alert!

Region: Conservation status by state

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) ⚘

Kalalau Valley Starviolet: A Rare Hawaiian Gem That’s Better Left Wild

Meet the Kalalau Valley starviolet (Hedyotis tryblium), one of Hawaii’s most elusive native treasures. If you’ve never heard of this plant before, you’re not alone – and there’s a very good reason why it’s not gracing gardens across the islands.

What Makes This Plant So Special?

The Kalalau Valley starviolet is a perennial shrub that’s as rare as it is beautiful. This multi-stemmed woody plant typically grows less than 13-16 feet tall, with several stems arising from near the ground. Like many Hawaiian natives, it’s perfectly adapted to its island home, but unlike others, it’s hanging on by a thread.

You might also see this plant listed under its scientific synonym, Kadua tryblium, but whatever you call it, it’s the same critically imperiled species.

Where Does It Call Home?

This remarkable plant is found exclusively in Hawaii, making it a true island endemic. As its common name suggests, it’s particularly associated with the dramatic Kalalau Valley region of Kauai, one of the most remote and pristine areas in the Hawaiian Islands.

The Conservation Reality Check

Here’s the important part: The Kalalau Valley starviolet has a Global Conservation Status of S1, which means it’s critically imperiled. In plain terms, this means there are typically five or fewer known occurrences of this plant in the wild, with very few remaining individuals – we’re talking fewer than 1,000 plants total.

This isn’t just rare – it’s on the edge of extinction.

Should You Plant It in Your Garden?

The short answer is: probably not, and here’s why. With such an extreme rarity status, every single plant in the wild is precious for the species’ survival. While we’re not saying you absolutely can’t grow it, we strongly recommend leaving this one to the conservation experts.

If you’re absolutely determined to include this species in a conservation garden or research project, make sure any plant material is:

  • Responsibly sourced through legitimate conservation programs
  • Properly permitted (Hawaii has strict regulations about native plants)
  • Part of a genuine conservation effort, not just garden decoration

Growing Conditions (For Conservation Purposes Only)

Based on its native habitat, the Kalalau Valley starviolet likely prefers:

  • Tropical Hawaiian climate conditions (USDA zones 10-12)
  • Well-draining soils (it has facultative upland status, meaning it usually grows in non-wetland areas)
  • The specific microclimate conditions found in its native Kauai habitat

However, detailed cultivation information is understandably limited given the plant’s conservation status.

Better Alternatives for Your Hawaiian Garden

Instead of trying to grow this rare beauty, consider these more common native Hawaiian alternatives that can give you that authentic island feel:

  • Other Hedyotis species that aren’t critically endangered
  • Native Hawaiian shrubs like ʻaʻaliʻi (Dodonaea viscosa)
  • Māmane (Sophora chrysophylla) if you’re at higher elevations
  • Native Hawaiian mints and other small shrubs

The Bottom Line

The Kalalau Valley starviolet represents something bigger than just a garden plant – it’s a reminder of Hawaii’s incredible biodiversity and the fragility of island ecosystems. Sometimes the best way to appreciate a rare plant is to support its conservation in the wild rather than trying to bring it home.

If you’re passionate about native Hawaiian plants (and you should be!), consider supporting local conservation organizations, participating in native plant restoration projects, or simply choosing more common native species for your own garden. Your local native plant society can point you toward beautiful, gardenable natives that won’t put additional pressure on critically imperiled species.

After all, the best gardens are the ones that work with nature, not against it.

Kalalau Valley Starviolet

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

Rubiales

Family

Rubiaceae Juss. - Madder family

Genus

Hedyotis L. - starviolet

Species

Hedyotis tryblium D.R. Herbst & W.L. Wagner - Kalalau Valley starviolet

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