Native Plants

Calistoga Popcornflower

Plagiobothrys strictus

USDA symbol: PLST2

annual forb

Lower 48 states: native

Meet the Calistoga popcornflower (Plagiobothrys strictus), one of California’s most endangered native plants. This tiny annual wildflower might not win any beauty contests, but it holds a special place in the hearts of conservation botanists and native plant enthusiasts. Before you start dreaming of adding this rare gem to your ...

Calistoga Popcornflower may be listed as rare in your area.
Global Conservation Status

Status: S1 | Critically imperiled: Typically 5 or fewer occurrences or under 1,000 remaining individuals.

United States

Status: Endangered | Endangered. In danger of extinction throughout all or a significant portion of its range.

Calistoga Popcornflower: A Rare Wetland Gem That’s Better Admired Than Grown

Meet the Calistoga popcornflower (Plagiobothrys strictus), one of California’s most endangered native plants. This tiny annual wildflower might not win any beauty contests, but it holds a special place in the hearts of conservation botanists and native plant enthusiasts. Before you start dreaming of adding this rare gem to your garden, though, there’s something important you need to know.

What Makes This Plant So Special (And So Rare)

The Calistoga popcornflower is what botanists call a forb – essentially a non-woody flowering plant that completes its entire life cycle in just one year. Like other members of the popcornflower family, it produces clusters of small white flowers that some say resemble tiny kernels of popped corn (hence the charming common name).

But here’s what makes this particular popcornflower extraordinary: it’s critically imperiled. With a global conservation status of S1 and listed as endangered in the United States, this little plant is hanging on by a thread. Typically, fewer than five populations exist worldwide, with fewer than 1,000 individual plants remaining in the wild.

Where in the World Can You Find It?

The Calistoga popcornflower is a true California endemic, found only in the Golden State. More specifically, it’s endemic to the Calistoga area in Napa County – talk about having a limited address! This incredibly restricted range makes it one of the most geographically confined plants in North America.

  • Species observed
  • No observations

A Wetland Specialist

This isn’t your typical garden annual. The Calistoga popcornflower is classified as an obligate wetland plant, meaning it almost always occurs in wetlands with saturated soils. It’s perfectly adapted to these soggy conditions but absolutely cannot survive in typical garden settings.

Should You Grow Calistoga Popcornflower?

The short answer: Please don’t. Here’s why this rare beauty should stay in the wild (or in the hands of qualified conservation professionals):

  • Extreme rarity: With so few plants left in existence, every individual in the wild is precious for the species’ survival
  • Specialized habitat needs: It requires specific wetland conditions that are nearly impossible to replicate in home gardens
  • Legal protections: As an endangered species, collecting seeds or plants from wild populations may be illegal
  • Conservation priority: Efforts should focus on protecting existing habitat rather than cultivation

What You Can Do Instead

If you’re inspired by the story of the Calistoga popcornflower, consider these alternatives:

  • Support wetland conservation organizations working to protect rare California plants
  • Plant other California native popcornflower species that are more common and suitable for gardens
  • Create habitat for pollinators with common native wildflowers in your area
  • Visit botanical gardens or nature preserves where rare plants are professionally maintained

A Conservation Success Story in the Making

While the Calistoga popcornflower’s story might seem sad, it’s actually a powerful reminder of why native plant conservation matters. Every rare species like this one represents millions of years of evolution and plays a unique role in its ecosystem. By learning about plants like the Calistoga popcornflower, we become better advocates for the wild spaces and native plants in our own communities.

Sometimes the best way to love a plant is to let it be wild and work to protect the places where it naturally belongs. The Calistoga popcornflower may be small and rare, but it has a big lesson to teach us about the preciousness of our native flora.

Plagiobothrys strictus 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. Plagiobothrys strictus is also known as:

Allocarya stricta | USDA symbol: ALST7

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: Asteridae
Order: Lamiales
Family: Boraginaceae Juss. - Borage family
Genus: Plagiobothrys Fisch. & C.A. Mey. - popcornflower

Species: Plagiobothrys strictus (Greene) I.M. Johnst. - Calistoga popcornflower

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