North America Native Plant

Kern County Milkvetch

Botanical name: Astragalus subvestitus

USDA symbol: ASSU8

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Kern County Milkvetch: A Rare California Native Worth Protecting Meet the Kern County milkvetch (Astragalus subvestitus), a little-known perennial that’s quietly holding down the fort in California’s arid landscapes. This unassuming member of the legume family might not win any beauty contests, but it’s got something far more valuable: it’s ...

Rare plant alert!

Region: Conservation status by state

Status: S3: 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 ⚘

Kern County Milkvetch: A Rare California Native Worth Protecting

Meet the Kern County milkvetch (Astragalus subvestitus), a little-known perennial that’s quietly holding down the fort in California’s arid landscapes. This unassuming member of the legume family might not win any beauty contests, but it’s got something far more valuable: it’s a true California original that’s become increasingly rare in our modern world.

What Makes This Plant Special?

The Kern County milkvetch is what botanists call an endemic species—meaning it’s found naturally in only one specific region. In this case, that’s California, where it has adapted to thrive in conditions that would make most garden plants throw in the trowel. As a perennial, it comes back year after year, quietly doing its part to support local ecosystems.

Where You’ll Find It Growing Wild

This California native has made its home exclusively in the Golden State, particularly in areas around Kern County (hence the name!). It’s perfectly adapted to the unique climate and soil conditions of this region, where it has evolved alongside other native species for thousands of years.

A Plant That Needs Our Help

Here’s where things get serious: Kern County milkvetch has a Global Conservation Status of S3, which means it’s considered vulnerable. With typically only 21 to 100 occurrences and between 3,000 to 10,000 individuals remaining, this plant is walking a tightrope toward extinction. Factors like habitat loss and environmental changes have made it increasingly difficult for this species to maintain stable populations.

Important: If you’re considering adding this plant to your garden, please only source it from reputable native plant nurseries that propagate from ethically collected seed or cuttings. Never collect plants or seeds from wild populations.

Garden Appeal and Landscape Role

Let’s be honest—Kern County milkvetch isn’t going to be the showstopper of your garden. Like most milkvetches, it produces small, pea-like flowers that are more charming than spectacular. But what it lacks in flashy blooms, it makes up for in ecological value and authentic California character.

This plant is perfect for:

  • Native California gardens focused on conservation
  • Xerophytic (drought-tolerant) landscapes
  • Educational gardens highlighting rare species
  • Restoration projects in appropriate habitats

Growing Conditions and Care

If you’re lucky enough to find responsibly sourced Kern County milkvetch, you’ll need to recreate its natural habitat as closely as possible. This likely means:

  • Well-draining, potentially alkaline soils
  • Full sun exposure
  • Minimal summer water once established
  • USDA hardiness zones 8-10 (based on its California range)

Fair warning: this isn’t a plant for beginners or those expecting instant gratification. Its specialized needs and slow establishment make it a project for dedicated native plant enthusiasts.

Supporting Pollinators and Wildlife

As a member of the legume family, Kern County milkvetch produces flowers that attract native bees and other small pollinators. While we don’t have extensive data on all its wildlife interactions, legumes typically support various insects and can provide food for seed-eating birds.

The Bottom Line: Should You Grow It?

Growing Kern County milkvetch is less about creating a stunning garden display and more about participating in conservation. If you’re passionate about preserving California’s botanical heritage and have experience with challenging native plants, this could be a meaningful addition to your garden.

However, if you’re new to native gardening or looking for easy-care plants with immediate visual impact, you might want to start with more common California natives like ceanothus, penstemon, or California poppies. Once you’ve mastered those, you can work your way up to rare gems like this one.

Remember: every responsibly grown Kern County milkvetch in cultivation is a small victory for conservation. Just make sure you’re getting your plant from ethical sources—the wild populations need every individual they can get.

Kern County 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 subvestitus (Jeps.) Barneby - Kern County milkvetch

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