Native Plants

Coastal Sandmat

Chamaesyce skottsbergii var. skottsbergii

USDA symbol: CHSKS

perennial subshrub

Hawaii: native

If you’re passionate about native Hawaiian plants and conservation gardening, you might have come across the coastal sandmat (Chamaesyce skottsbergii var. skottsbergii). This little-known native shrub represents both an opportunity and a responsibility for dedicated gardeners who want to support Hawaii’s unique flora. Coastal sandmat is a perennial shrub that’s ...

Coastal Sandmat may be listed as rare in your area.
Global Conservation Status

Status: S2T2 | Subspecies or variety is imperiled: Extremely rare. Typically 6 to 20 occurrences or 1,000 to 3,000 remaining individuals.

Coastal Sandmat: A Rare Hawaiian Native Worth Protecting in Your Garden

If you’re passionate about native Hawaiian plants and conservation gardening, you might have come across the coastal sandmat (Chamaesyce skottsbergii var. skottsbergii). This little-known native shrub represents both an opportunity and a responsibility for dedicated gardeners who want to support Hawaii’s unique flora.

What Is Coastal Sandmat?

Coastal sandmat is a perennial shrub that’s as Hawaiian as it gets – this species is found nowhere else in the world except the Hawaiian Islands. As a member of the spurge family, it typically grows as a multi-stemmed woody plant, usually staying under 13-16 feet in height, though it can sometimes grow taller or develop a single stem depending on environmental conditions.

Where Does It Grow Naturally?

This endemic Hawaiian species is found exclusively within the Hawaiian Islands. Its natural range is limited to specific coastal and dry habitat areas throughout Hawaii, making it a true island treasure.

  • Species observed
  • No observations

The Rarity Factor: Why This Matters

Here’s something every gardener considering this plant needs to know: coastal sandmat has a Global Conservation Status of S2T2, indicating it’s quite rare in the wild. This rarity status means that while growing this plant can contribute to conservation efforts, it comes with an important caveat – you must source your plants responsibly.

Never collect plants or seeds from wild populations. Instead, work with reputable native plant nurseries, botanical gardens, or conservation organizations that propagate plants ethically from cultivated stock.

Garden Appeal and Landscape Use

While detailed information about coastal sandmat’s specific aesthetic qualities and growing requirements is limited, its status as a native Hawaiian shrub suggests it would be most appropriate for:

  • Native Hawaiian plant gardens
  • Conservation-focused landscapes
  • Educational or botanical gardens
  • Xerophytic or drought-tolerant plantings

Given its coastal associations, it likely tolerates salt spray and sandy soils, making it potentially valuable for seaside gardens in Hawaii.

Growing Conditions and Care

As a Hawaiian native adapted to coastal and dry environments, coastal sandmat likely prefers:

  • Well-draining, sandy soils
  • Full sun to partial shade
  • Low to moderate water once established
  • Protection from cold temperatures (suitable for USDA zones 10-12, typical for Hawaii)

Like many members of the spurge family, it may have a milky sap that can be irritating to skin, so handle with care during planting and maintenance.

Supporting Conservation Through Gardening

By choosing to grow coastal sandmat in your Hawaiian garden, you’re participating in a larger conservation effort. Native plants like this one support local ecosystems, provide habitat for native insects and birds, and help preserve Hawaii’s unique botanical heritage for future generations.

The Bottom Line

Coastal sandmat isn’t your typical garden center find, and that’s exactly what makes it special. If you’re a dedicated native plant enthusiast in Hawaii with access to ethically sourced plants, adding this rare species to your collection can be both rewarding and meaningful. Just remember – with rarity comes responsibility. Always source plants through proper conservation channels and never harvest from wild populations.

This plant represents the kind of gardening that goes beyond aesthetics to embrace conservation, education, and the preservation of Hawaii’s irreplaceable natural heritage.

Chamaesyce skottsbergii var. skottsbergii is also known as...

Often we refer to plants by their common names. When shopping for plants the scientific name is the best way to positively identify the plant species you desire. But some plants have more than one name! While it doesn't happen often, nurseries might display one name while you're searching for another. Chamaesyce skottsbergii var. skottsbergii is also known as:

Chamaesyce skottsbergii Croizat & var. audens & | USDA symbol: CHSKA
Chamaesyce skottsbergii Croizat & var. kalaeloana & | USDA symbol: CHSKK
Euphorbia skottsbergii | USDA symbol: EUSK
Euphorbia skottsbergii Sherff var. audens | USDA symbol: EUSKA
Euphorbia skottsbergii Sherff var. kalaeloana | USDA symbol: EUSKK
Euphorbia skottsbergii Sherff var. typica | USDA symbol: EUSKT

Why do some plants have more than one name? Over time plant species may be renamed for a few reasons:

  1. Botanists in different regions named the same plant without knowing it had already been classified.
  2. A species was reclassified after scientific advances in, for example, DNA analysis.
  3. Slight variations within a species are sometimes mistakenly identified as entirely new species.

Classification

Group: Dicot
Kingdom: Plantae - Plants
Subkingdom: Tracheobionta - Vascular plants
Superdivision: Spermatophyta - Seed plants
Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida - Dicotyledons
Subclass: Rosidae
Order: Euphorbiales
Family: Euphorbiaceae Juss. - Spurge family
Genus: Chamaesyce Gray - sandmat

Species: Chamaesyce skottsbergii (Sherff) Croizat & O. Deg. - coastal sandmat

Variety: Chamaesyce skottsbergii (Sherff) Croizat & O. Deg. var. skottsbergii - coastal sandmat

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