North America Native Plant

Beckwith’s Milkvetch

Botanical name: Astragalus beckwithii var. sulcatus

USDA symbol: ASBES

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Beckwith’s Milkvetch: A Rare Idaho Native Worth Knowing If you’re passionate about native plants and love discovering botanical treasures, you might have stumbled across Beckwith’s milkvetch (Astragalus beckwithii var. sulcatus). This perennial wildflower represents one of nature’s more specialized creations – a plant so particular about where it calls home ...

Rare plant alert!

Region: Conservation status by state

Status: S5T3: 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. ⚘ Secure: At very low or no risk of extinction in the jurisdiction due to a very extensive range, abundant populations or occurrences, with little to no concern from declines or threats. ⚘

Beckwith’s Milkvetch: A Rare Idaho Native Worth Knowing

If you’re passionate about native plants and love discovering botanical treasures, you might have stumbled across Beckwith’s milkvetch (Astragalus beckwithii var. sulcatus). This perennial wildflower represents one of nature’s more specialized creations – a plant so particular about where it calls home that it’s found naturally in just one state: Idaho.

What Makes This Plant Special

Beckwith’s milkvetch belongs to the legume family, making it a cousin to familiar garden favorites like beans and peas. As a perennial, this hardy plant returns year after year, potentially becoming a long-term resident in the right garden setting. Its native status in the lower 48 states makes it an authentic piece of American botanical heritage.

Where You’ll Find It Growing Wild

This particular variety of Beckwith’s milkvetch has a very limited natural range, calling only Idaho home. This restricted distribution makes it quite the botanical rarity – you won’t accidentally stumble across it during a casual nature walk in most parts of the country.

A Word of Caution for Gardeners

Here’s where things get interesting (and important). With a conservation status of S5T3, this plant falls into a category that requires careful consideration. While the exact meaning of this status isn’t clearly defined in available resources, any plant with such limited geographic distribution deserves our respect and protection.

If you’re considering adding this plant to your garden, please ensure you source it responsibly. This means:

  • Never collect plants or seeds from wild populations
  • Purchase only from reputable native plant nurseries that propagate their stock
  • Verify that any plant material has been ethically sourced
  • Consider whether this rare plant is the best choice for your garden, or if other native alternatives might be more appropriate

The Growing Challenge

Unfortunately, detailed growing information for this specific variety is quite limited. This scarcity of cultivation guidance is actually pretty telling – it suggests that Beckwith’s milkvetch isn’t commonly grown in home gardens, likely due to its specialized habitat requirements or rarity.

What we do know is that as a native Idaho plant, it has evolved to thrive in specific conditions that might be challenging to replicate in typical garden settings. Like many native plants from western states, it likely prefers well-draining soils and may have adapted to Idaho’s particular climate patterns.

Should You Grow It?

While the romantic appeal of growing a rare native plant is undeniable, this might be one of those cases where admiration from afar is the more responsible choice. The limited availability of information, combined with its restricted natural range, suggests that Beckwith’s milkvetch is better left to specialized botanical gardens, research institutions, or conservation efforts rather than home gardens.

Better Alternatives for Your Native Garden

If you’re drawn to native legumes that support local ecosystems, consider these more readily available and garden-friendly alternatives:

  • Other Astragalus species native to your region
  • Wild lupines (Lupinus species)
  • Native clovers (Trifolium species)
  • Leadplant (Amorpha canescens)

These alternatives can provide similar ecological benefits while being more appropriate for home cultivation and easier to source responsibly.

The Bottom Line

Beckwith’s milkvetch represents the fascinating diversity of North America’s native flora, but it’s also a reminder that not every plant is meant for our gardens. Sometimes the best way to appreciate and protect rare native plants is to support conservation efforts and choose more common native species that can thrive in our home landscapes while still supporting local wildlife and ecosystems.

If you’re in Idaho and have the opportunity to observe this plant in its natural habitat, consider yourself lucky – just remember to look but not touch, and definitely don’t dig!

Beckwith’s Milkvetch

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

Astragalus L. - milkvetch

Species

Astragalus beckwithii Torr. & A. Gray - Beckwith's milkvetch

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