North America Native Plant

California Goldenbanner

Botanical name: Thermopsis californica var. argentata

USDA symbol: THCAA

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Thermopsis argentata Greene (THAR3)  âš˜  Thermopsis gracilis Howell var. argentata (Greene) Jeps. (THGRA)  âš˜  Thermopsis macrophylla Hook. & Arn. var. argentata (Greene) Jeps. (THMAA2)   

California Goldenbanner: A Rare Native Gem for California Gardens Meet California goldenbanner (Thermopsis californica var. argentata), a fascinating native perennial that’s flying under the radar in most California gardens. This lesser-known variety of the goldenbanner family might just be the native plant treasure you’ve been looking for – if you ...

Rare plant alert!

Region: Conservation status by state

Status: S3T3: 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. ⚘

California Goldenbanner: A Rare Native Gem for California Gardens

Meet California goldenbanner (Thermopsis californica var. argentata), a fascinating native perennial that’s flying under the radar in most California gardens. This lesser-known variety of the goldenbanner family might just be the native plant treasure you’ve been looking for – if you can find it!

What Makes California Goldenbanner Special?

California goldenbanner is a true California native, belonging to the forb family – which is just a fancy way of saying it’s an herbaceous perennial without woody stems. Think of it as nature’s way of creating a sturdy, long-lasting garden plant that comes back year after year without the commitment of a shrub or tree.

As a perennial forb, this plant puts its energy into its root system and underground structures, allowing it to persist through California’s varied seasons and return reliably each growing season.

Where Does It Call Home?

This golden beauty is exclusively native to California, making it a perfect choice for gardeners wanting to support local ecosystems and create authentic California landscapes. Its natural range is limited to the Golden State, where it has evolved alongside local wildlife and adapted to regional growing conditions.

A Word About Rarity

Here’s something important to know: California goldenbanner var. argentata has a conservation status of S3T3, which indicates it may be uncommon or have limited distribution. This means if you’re lucky enough to find this plant, you should source it responsibly from reputable native plant nurseries that propagate their own stock rather than wild-collecting.

Growing rare natives like this one in your garden actually helps conservation efforts by maintaining genetic diversity and creating seed sources for the future.

The Challenge: Limited Growing Information

Here’s where things get a bit tricky – detailed growing information for this specific variety is surprisingly scarce. While we know it’s a California native perennial forb, specific details about its preferred growing conditions, mature size, care requirements, and garden performance are not well documented.

This is actually pretty common with rare or less-studied plant varieties. Sometimes the most interesting natives are the ones that haven’t made it into mainstream horticulture guides yet!

Should You Grow California Goldenbanner?

Consider growing it if:

  • You’re passionate about rare California natives
  • You want to support plant conservation through cultivation
  • You enjoy being a plant pioneer and experimenting with uncommon species
  • You can source it from a reputable native plant nursery

You might want to wait if:

  • You’re new to native gardening and want well-documented plants
  • You need specific size or performance guarantees for a landscape project
  • You can’t find responsibly sourced plants

Growing Tips (What We Know)

While specific care instructions for this variety are limited, here’s what we can reasonably assume based on its California native status:

  • Likely prefers well-draining soil (most California natives do)
  • Probably drought-tolerant once established (typical of native forbs)
  • May benefit from some summer water in inland areas
  • Should be hardy in California’s climate zones

The Bottom Line

California goldenbanner var. argentata represents the exciting frontier of native plant gardening – those special plants that are authentic to our region but haven’t yet been fully explored horticulturally. If you can find responsibly sourced plants and you’re up for a gardening adventure, this rare native could be a unique addition to your California garden.

Just remember to source responsibly, be patient as you learn its preferences, and consider yourself a steward of California’s plant heritage. After all, every common garden plant was once a rare, unknown species that someone decided to give a chance!

California Goldenbanner

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Fabales

Family

Fabaceae Lindl. - Pea family

Genus

Thermopsis R. Br. - goldenbanner

Species

Thermopsis californica S. Watson - California goldenbanner

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