North America Native Plant

Robust Starwort

Botanical name: Stellaria oxyphylla

USDA symbol: STOX2

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Alsine oxyphylla (B.L. Rob.) A. Heller (ALOX3)   

Robust Starwort: A Rare Native Gem Worth Protecting Meet robust starwort (Stellaria oxyphylla), a delicate perennial wildflower that’s become something of a botanical treasure. This petite member of the carnation family might not make headlines like flashy garden center favorites, but it holds a special place in the world of ...

Rare plant alert!

Region: Conservation status by state

Status: S1S2: 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) ⚘ Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘

Robust Starwort: A Rare Native Gem Worth Protecting

Meet robust starwort (Stellaria oxyphylla), a delicate perennial wildflower that’s become something of a botanical treasure. This petite member of the carnation family might not make headlines like flashy garden center favorites, but it holds a special place in the world of native plant conservation.

What Makes Robust Starwort Special?

Robust starwort is a charming little forb—that’s botanist-speak for a soft-stemmed herbaceous plant—that produces clusters of tiny white, star-shaped flowers. Despite its robust name, this perennial is actually quite delicate in appearance, with narrow leaves and a low-growing habit that makes it perfect for tucking into rock gardens or naturalizing in woodland settings.

Also known scientifically by its former name Alsine oxyphylla, this native wildflower belongs exclusively to the American landscape, specifically calling Idaho home.

Where Does Robust Starwort Grow?

Here’s where things get interesting—and a bit concerning. Robust starwort is found only in Idaho, making it what botanists call an endemic species. This extremely limited geographic distribution is part of what makes this plant so special, but also so vulnerable.

A Conservation Success Story in the Making

Before you start searching online nurseries, there’s something important you need to know: robust starwort carries a Global Conservation Status of S1S2, which means it’s considered very rare to rare. This isn’t a plant you’ll find at your local garden center, and that’s actually a good thing for conservation efforts.

If you’re interested in growing this rare beauty, here’s the responsible approach:

  • Only source plants or seeds from reputable native plant societies or conservation organizations
  • Never collect from wild populations
  • Consider supporting habitat conservation efforts instead
  • Look for similar, more common Stellaria species as alternatives

Growing Conditions and Care

For those fortunate enough to obtain ethically sourced robust starwort, here’s what this little gem prefers:

Climate: Hardy in USDA zones 4-7, this plant thrives in the cooler temperatures of its native Idaho range.

Soil and Water: Like many native wildflowers, robust starwort appreciates well-draining soil that stays consistently moist but not waterlogged. Think of the conditions you’d find in a mountain meadow—cool, fresh, and naturally irrigated.

Light: Partial shade to filtered sunlight works best, mimicking the dappled light conditions of its natural habitat.

Maintenance: Once established, this perennial requires minimal care. The key is providing the right conditions from the start and then leaving it largely undisturbed.

Garden Design Ideas

If you’re working with responsibly sourced plants, robust starwort shines in:

  • Rock gardens where its delicate texture provides contrast
  • Native plant collections focused on regional flora
  • Woodland edges and naturalized areas
  • Conservation-minded landscapes

Supporting Pollinators and Wildlife

Those small white flowers aren’t just pretty—they serve an important ecological function by providing nectar and pollen for various small pollinators, including native flies and tiny bees. Every rare plant that maintains its foothold in the ecosystem helps support the intricate web of relationships that keep our natural world functioning.

The Bottom Line

Robust starwort represents something bigger than just another pretty wildflower—it’s a reminder of how precious and fragile our native plant communities can be. While most gardeners won’t have the opportunity to grow this rare species, we can all support its conservation by:

  • Choosing other native plants for our gardens
  • Supporting organizations working to protect rare plant habitats
  • Learning about and appreciating the native plants in our own regions
  • Never collecting plants from wild populations

Sometimes the greatest act of love for a plant is simply knowing it exists and working to ensure it always will. Robust starwort may be small and rare, but it’s a perfect example of why every native species matters in the grand tapestry of our natural heritage.

Robust Starwort

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

Stellaria L. - starwort

Species

Stellaria oxyphylla B.L. Rob. - robust starwort

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