North America Native Plant

Slender Goldenbanner

Botanical name: Thermopsis gracilis var. ovata

USDA symbol: THGRO

Life cycle: perennial

Habit: forb

Native status: Non-native, reproduces and persists in the wild in Canada âš˜ Native to the lower 48 states  

Synonyms: Thermopsis montana Nutt. var. ovata (B.L. Rob. ex Piper) H. St. John (THMOO2)  âš˜  Thermopsis ovata B.L. Rob. ex Piper (THOV2)  âš˜  Thermopsis rhombifolia (Nutt. ex Pursh) Nutt. ex Richardson var. ovata (B.L. Rob. ex Piper) Isely (THRHO)   

Slender Goldenbanner: A Lesser-Known Western Wildflower If you’ve been searching for unique native plants to add diversity to your garden, you might have stumbled across slender goldenbanner (Thermopsis gracilis var. ovata). This perennial wildflower belongs to the legume family and represents a specific variety of the broader slender goldenbanner species. ...

Rare plant alert!

Region: Conservation status by state

Status: S4T3T4: Status is uncertain but is somewhere between the following rankings: 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 ⚘

Slender Goldenbanner: A Lesser-Known Western Wildflower

If you’ve been searching for unique native plants to add diversity to your garden, you might have stumbled across slender goldenbanner (Thermopsis gracilis var. ovata). This perennial wildflower belongs to the legume family and represents a specific variety of the broader slender goldenbanner species. While not as commonly discussed as its more famous cousins, this plant has its own interesting story to tell.

What Exactly Is Slender Goldenbanner?

Slender goldenbanner is a herbaceous perennial forb, which simply means it’s a non-woody flowering plant that comes back year after year. Unlike shrubs or trees, it lacks significant woody tissue and instead relies on underground structures to survive winter and regrow each spring.

You might also encounter this plant listed under several scientific synonyms in older botanical references, including Thermopsis montana var. ovata or Thermopsis ovata, which can make researching this particular variety a bit like botanical detective work!

Where Does It Come From?

This variety has an interesting geographic story. While it’s considered native to several western United States including Idaho, Montana, Nevada, Oregon, and Washington, it has also established itself in parts of Canada, specifically Prince Edward Island and Newfoundland, where it’s classified as a non-native species that reproduces on its own.

The Challenge with This Particular Variety

Here’s where things get honest: specific information about Thermopsis gracilis var. ovata is surprisingly limited in readily available horticultural and botanical literature. This particular variety seems to fly under the radar compared to other Thermopsis species that are more commonly cultivated and studied.

What we do know is limited:

  • It’s a perennial that should return each year
  • As a legume family member, it likely has nitrogen-fixing capabilities
  • Its natural range suggests it’s adapted to cooler, northern climates
  • The goldenbanner name suggests yellow flowers typical of the genus

Should You Plant It?

Given the limited specific information available and the unclear cultivation requirements for this particular variety, it might be challenging for home gardeners to grow successfully. The lack of readily available seeds or plants through commercial sources also presents a practical hurdle.

If you’re drawn to the Thermopsis genus for your garden, you might have better success with more commonly available species like:

  • Carolina bush pea (Thermopsis villosa)
  • Golden banner (Thermopsis montana)
  • Other regional Thermopsis species with established cultivation guidelines

A Word of Caution

Since this variety has established itself outside its native range, and we don’t have clear information about its growth habits or potential invasiveness, it’s worth exercising caution. Before considering cultivation, check with your local extension office or native plant society about appropriate alternatives that are definitely native to your specific region.

The Bottom Line

While slender goldenbanner var. ovata is undoubtedly an interesting plant from a botanical perspective, the limited available information makes it a challenging choice for most gardeners. Sometimes the most responsible approach is to admire a plant’s uniqueness while choosing better-documented alternatives that will give you a higher chance of gardening success.

If you’re passionate about growing lesser-known native plants, consider connecting with botanical gardens, native plant societies, or university extension programs in regions where this variety naturally occurs. They might have more detailed cultivation information or be able to point you toward similar, better-documented species that would thrive in your garden.

Slender 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 gracilis Howell - slender goldenbanner

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