North America Native Plant

Herbst’s Sandmat

Botanical name: Chamaesyce herbstii

USDA symbol: CHHE3

Life cycle: perennial

Habit: tree

Native status: Native to Hawaii  

Synonyms: Chamaesyce forbesii (Sherff) Croizat & O. Deg. var. grandifolia Hillebr. (CHFOG)  âš˜  Chamaesyce rockii (Forbes) Croizat & O. Deg. var. grandifolia (Hillebr.) Koutnik (CHROG)  âš˜  Euphorbia herbstii (W.L. Wagner) Oudejans (EUHE6)  âš˜  Euphorbia rockii Forbes var. grandifolia (Hillebr.) Oudejans (EUROG)   

Herbst’s Sandmat: A Rare Hawaiian Treasure Worth Protecting Meet Herbst’s sandmat (Chamaesyce herbstii), one of Hawaii’s most endangered native plants. This remarkable species isn’t your typical garden center find – and for good reason. With fewer than 1,000 individuals remaining in the wild, this critically imperiled tree deserves our attention ...

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

Herbst’s Sandmat: A Rare Hawaiian Treasure Worth Protecting

Meet Herbst’s sandmat (Chamaesyce herbstii), one of Hawaii’s most endangered native plants. This remarkable species isn’t your typical garden center find – and for good reason. With fewer than 1,000 individuals remaining in the wild, this critically imperiled tree deserves our attention and protection.

What Makes Herbst’s Sandmat Special?

Don’t let the name fool you – Herbst’s sandmat isn’t a ground-hugging mat at all! This perennial wonder is actually a small tree that can reach heights of 13-16 feet or more. It’s a woody plant with a single trunk, though environmental conditions sometimes encourage a shorter, multi-stemmed growth pattern.

As a member of the spurge family, this Hawaiian native has that distinctive succulent-like appearance that makes it stand out in any landscape. Its small leaves and inconspicuous flowers might seem modest, but there’s something undeniably charming about its understated elegance.

Where Does It Call Home?

Herbst’s sandmat is endemic to Hawaii, meaning you won’t find it naturally occurring anywhere else on Earth. This makes it extra special – and extra vulnerable. The species has adapted to Hawaii’s unique volcanic soils and climate conditions over thousands of years.

A Plant in Crisis

Here’s where things get serious. Herbst’s sandmat has a Global Conservation Status of S1, which translates to Critically Imperiled. In the United States, it’s listed as Endangered. With typically five or fewer occurrences and very few remaining individuals, this species is teetering on the brink of extinction.

What does this mean for gardeners? If you’re lucky enough to encounter this plant, it should only be through responsible, legal sources that support conservation efforts. Never collect from wild populations – every individual counts toward the species’ survival.

Growing Herbst’s Sandmat: For the Dedicated Conservationist

If you can obtain Herbst’s sandmat through proper conservation channels, here’s what you need to know about growing this Hawaiian treasure:

Ideal Growing Conditions

  • Climate: USDA hardiness zones 10-12 (tropical and subtropical)
  • Sunlight: Full sun to partial shade
  • Soil: Well-draining soil is absolutely critical
  • Water: Drought tolerant once established, but needs regular water when young

Planting and Care Tips

  • Ensure excellent drainage – this plant cannot tolerate waterlogged conditions
  • Plant in a protected location away from strong winds
  • Water regularly during establishment, then reduce frequency
  • Minimal fertilization needed – these plants are adapted to nutrient-poor volcanic soils

Garden Role and Design Ideas

In the right setting, Herbst’s sandmat makes an excellent specimen plant for native Hawaiian gardens or drought-tolerant landscapes. Its unique form and conservation story make it a conversation starter and educational opportunity. Consider it for:

  • Native plant gardens focusing on Hawaiian species
  • Xeriscaping and water-wise landscapes
  • Rock gardens with good drainage
  • Educational or botanical gardens

Supporting Conservation

The best way most gardeners can help Herbst’s sandmat is by supporting Hawaiian native plant conservation organizations and botanical gardens working to preserve this species. Some facilities may offer educational programs or volunteer opportunities related to endangered plant conservation.

If you’re passionate about Hawaiian natives and have the right growing conditions, consider planting other endangered Hawaiian species that may be more readily available through conservation programs. Every garden that includes native Hawaiian plants helps raise awareness about these incredible, irreplaceable treasures.

The Bottom Line

Herbst’s sandmat represents both the beauty and fragility of Hawaii’s native ecosystems. While most of us won’t have the opportunity to grow this rare species, learning about it reminds us of the importance of protecting our native plants – wherever we call home. If you do encounter this plant through proper channels, consider yourself a conservation partner in one of nature’s most important rescue missions.

Herbst’s Sandmat

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Euphorbiales

Family

Euphorbiaceae Juss. - Spurge family

Genus

Chamaesyce Gray - sandmat

Species

Chamaesyce herbstii W.L. Wagner - Herbst's sandmat

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