North America Native Plant

Doublehorn Calicoflower

Botanical name: Downingia bicornuta var. bicornuta

USDA symbol: DOBIB

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Doublehorn Calicoflower: A Tiny Treasure for Specialized Native Gardens If you’ve ever wondered about those charming little blue wildflowers that pop up in California’s vernal pools, you might be looking at the doublehorn calicoflower (Downingia bicornuta var. bicornuta). This petite annual native is like the botanical equivalent of a shooting ...

Rare plant alert!

Region: Conservation status by state

Status: S3S4T3T4: Status is uncertain but is somewhere between the following rankings: Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘ Subspecies or variety is vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals. ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘ Subspecies or varieties is apparently secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the region or more than 10,000 individuals ⚘

Doublehorn Calicoflower: A Tiny Treasure for Specialized Native Gardens

If you’ve ever wondered about those charming little blue wildflowers that pop up in California’s vernal pools, you might be looking at the doublehorn calicoflower (Downingia bicornuta var. bicornuta). This petite annual native is like the botanical equivalent of a shooting star – spectacular when it appears, but requiring just the right conditions to shine.

What Makes Doublehorn Calicoflower Special

The doublehorn calicoflower is a true western native, naturally occurring across California, Idaho, Nevada, and Oregon. As an annual forb, it completes its entire life cycle in a single growing season, making the most of brief seasonal windows when conditions are just right.

This plant calls the western states of California, Idaho, Nevada, and Oregon home, where it has adapted to some pretty unique growing conditions that most garden plants would find downright inhospitable.

A Plant with Specific Needs

Here’s where things get interesting (and challenging): doublehorn calicoflower is a vernal pool specialist. These temporary wetlands flood during winter rains and gradually dry out through spring and summer. It’s like nature’s own seasonal water feature, and this little wildflower has evolved to thrive in this boom-and-bust water cycle.

The plant produces delicate blue flowers that are perfectly sized for small native pollinators. While we don’t have complete data on all its wildlife interactions, plants in vernal pool ecosystems typically support specialized communities of native bees and other beneficial insects.

Should You Grow Doublehorn Calicoflower?

This is where we need to have an honest conversation. The doublehorn calicoflower has a conservation status that suggests it may be somewhat rare or declining in parts of its range. This makes it an important plant to preserve, but also means you’ll want to be extra thoughtful about how you source it.

Reasons to consider it:

  • Supporting native biodiversity in specialized ecosystems
  • Attracting native pollinators
  • Creating authentic vernal pool or seasonal wetland gardens
  • Educational value for understanding unique ecosystems

Challenges to consider:

  • Requires very specific seasonal wet-dry cycles
  • Not suitable for typical garden conditions
  • May be difficult to source responsibly
  • Success depends on recreating specialized habitat

Growing Conditions and Care

If you’re determined to try growing doublehorn calicoflower, you’ll need to think like a vernal pool. This means:

  • Full sun exposure
  • Clay or heavy soils that hold water
  • Seasonal flooding from late fall through early spring
  • Complete drying out during summer months
  • USDA zones 8-10, primarily in Mediterranean climate regions

This isn’t a plant for casual gardeners or typical flower beds. You’d essentially need to create or have access to a seasonal wetland area that mimics natural vernal pools.

Sourcing Responsibly

Given its conservation status, if you’re interested in this plant, make sure to:

  • Source seeds or plants only from reputable native plant nurseries
  • Never collect from wild populations
  • Consider participating in habitat restoration projects instead
  • Connect with local native plant societies for guidance

The Bottom Line

Doublehorn calicoflower is a fascinating piece of western native flora that plays an important role in specialized ecosystems. While it’s probably not the right choice for most home gardens due to its very specific requirements, it’s worth knowing about and protecting. If you’re interested in supporting vernal pool ecosystems, consider visiting and supporting conservation of natural vernal pools, or participating in restoration projects where this little blue beauty can thrive in its proper habitat.

For most gardeners looking to support native pollinators and biodiversity, there are many other native annuals that are easier to grow and more adaptable to typical garden conditions while still providing important ecological benefits.

Doublehorn Calicoflower

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

Campanulales

Family

Campanulaceae Juss. - Bellflower family

Genus

Downingia Torr. - calicoflower

Species

Downingia bicornuta A. Gray - doublehorn calicoflower

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