North America Native Plant

Mariposa Erigeron

Botanical name: Erigeron mariposanus

USDA symbol: ERMA15

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Mariposa Erigeron: A Lost Treasure of California’s Native Flora In the world of native gardening, some plants capture our hearts not just for their beauty, but for their stories of loss and hope. Meet the Mariposa erigeron (Erigeron mariposanus), a delicate wildflower that represents one of California’s botanical mysteries—a species ...

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 ⚘

Mariposa Erigeron: A Lost Treasure of California’s Native Flora

In the world of native gardening, some plants capture our hearts not just for their beauty, but for their stories of loss and hope. Meet the Mariposa erigeron (Erigeron mariposanus), a delicate wildflower that represents one of California’s botanical mysteries—a species that may have vanished from the wild but continues to inspire conservation efforts across the Golden State.

What Is Mariposa Erigeron?

Mariposa erigeron is a perennial forb native to California, belonging to the diverse and beloved aster family. Like its cousins in the Erigeron genus, this plant would have produced charming daisy-like flowers with delicate petals surrounding sunny yellow centers. As a herbaceous perennial, it lacked woody stems but returned year after year from its root system—at least, it did when it still grew in the wild.

A Tale of Rarity and Loss

Important Conservation Alert: Mariposa erigeron carries a Global Conservation Status of SH—Possibly Extirpated. This means the species is known only from historical records, with no confirmed sightings in recent decades. While there’s still hope for rediscovery, this little wildflower may have already disappeared from California’s landscapes forever.

The species was historically found in California, with records pointing to the Mariposa County area (hence its common name). Today, botanists and conservationists continue to search for surviving populations, holding onto hope that this resilient native might still persist in some forgotten corner of its former range.

Should You Plant Mariposa Erigeron?

Here’s where things get complicated—and critically important. If you’re passionate about native plants and conservation, Mariposa erigeron represents both an inspiration and a responsibility. Given its possibly extirpated status, any cultivation of this species must be approached with extreme caution and ethics.

If Plant Material Becomes Available

Should seeds or plants ever become available through legitimate conservation efforts, consider these guidelines:

  • Source responsibly: Only obtain material from reputable botanical institutions or conservation programs
  • Verify authenticity: Ensure any material is genetically verified as true Erigeron mariposanus
  • Support conservation: Consider your garden as part of a larger conservation effort
  • Share knowledge: Document your growing experience to help conservation efforts

Growing Conditions and Care

While specific growing requirements for Mariposa erigeron remain somewhat mysterious due to its rarity, we can make educated guesses based on its California native status and the needs of related Erigeron species:

  • Climate: Likely suited for USDA zones 8-10, matching California’s Mediterranean climate
  • Soil: Probably prefers well-draining soils, typical of California natives
  • Water: Moderate water needs, with drought tolerance once established
  • Sun exposure: Full sun to partial shade, based on related species
  • Maintenance: Minimal care requirements, as with most native California perennials

Alternative Native Choices

While we hope for Mariposa erigeron’s rediscovery and potential cultivation, California gardeners can support native ecosystems by planting related species that are readily available:

  • Santa Barbara daisy (Erigeron karvinskianus)
  • Seaside daisy (Erigeron glaucus)
  • Showy fleabane (Erigeron speciosus)
  • Other native California asters and sunflowers

The Bigger Picture

Mariposa erigeron serves as a poignant reminder of what we stand to lose when native habitats disappear. Whether this species still exists in the wild or has already vanished, its story underscores the importance of protecting native plant communities and supporting conservation efforts.

By choosing to plant native species in our gardens—whether it’s the possibly extinct Mariposa erigeron or its thriving relatives—we create stepping stones for wildlife, preserve genetic diversity, and honor the intricate web of life that makes California’s ecosystems so remarkable.

Sometimes the most important plants in our native gardening journey are the ones that remind us why this work matters in the first place.

Mariposa Erigeron

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

Asterales

Family

Asteraceae Bercht. & J. Presl - Aster family

Genus

Erigeron L. - fleabane

Species

Erigeron mariposanus Congdon - Mariposa erigeron

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