North America Native Plant

Chestnut Milkvetch

Botanical name: Astragalus castaneiformis

USDA symbol: ASCA15

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Astragalus castaneiformis S. Watson var. typicus Barneby (ASCAT)   

Chestnut Milkvetch: A Native Arizona Gem for Your Garden If you’re looking to add some authentic southwestern character to your garden, chestnut milkvetch (Astragalus castaneiformis) might just be the native plant you’ve been searching for. This perennial member of the legume family brings a touch of the Arizona desert right ...

Rare plant alert!

Region: Conservation status by state

Status: S3S4: 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 ⚘ 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 ⚘

Chestnut Milkvetch: A Native Arizona Gem for Your Garden

If you’re looking to add some authentic southwestern character to your garden, chestnut milkvetch (Astragalus castaneiformis) might just be the native plant you’ve been searching for. This perennial member of the legume family brings a touch of the Arizona desert right to your backyard, and it’s got some pretty compelling reasons to earn a spot in your landscape.

What Makes Chestnut Milkvetch Special?

Chestnut milkvetch is a true Arizona native, naturally occurring in the diverse ecosystems of the Grand Canyon State. As a perennial plant, it offers the gift that keeps on giving – returning year after year once established. Being part of the Astragalus genus, it’s related to other milkvetches that have adapted to thrive in challenging desert conditions.

Where Does It Come From?

This hardy native calls Arizona home, where it has evolved to handle the unique challenges of southwestern growing conditions. Its natural range within the lower 48 states makes it a perfect choice for gardeners wanting to support local ecosystems and preserve regional plant heritage.

Why Plant Chestnut Milkvetch?

There are several compelling reasons to consider this native beauty:

  • Native plant benefits: Supports local wildlife and fits naturally into regional ecosystems
  • Low maintenance: Once established, native plants typically require less water and care than non-natives
  • Drought tolerance: As an Arizona native, it’s naturally adapted to arid conditions
  • Authentic landscape character: Adds genuine southwestern appeal to your garden

Growing Conditions and Care

While specific growing requirements for chestnut milkvetch aren’t well-documented, we can look to its natural Arizona habitat for clues. Like most desert natives, it likely prefers:

  • Well-draining soil (essential for preventing root rot)
  • Full sun to partial shade
  • Minimal water once established
  • Good air circulation

As a perennial, chestnut milkvetch will establish a root system over time, making it increasingly drought-tolerant and self-sufficient.

A Word About Responsible Sourcing

Chestnut milkvetch has a conservation status that suggests it may be somewhat uncommon in the wild. If you decide to add this plant to your garden, make sure you’re purchasing from reputable native plant nurseries that propagate their stock rather than collecting from wild populations. This helps protect natural stands while still allowing you to enjoy this beautiful native.

Garden Design Ideas

This Arizona native works beautifully in:

  • Desert and xeriscape gardens
  • Native plant landscapes
  • Rock gardens with good drainage
  • Wildlife-friendly plantings
  • Low-water landscape designs

The Bottom Line

Chestnut milkvetch represents an opportunity to grow something truly special – a plant that belongs in Arizona’s landscape and supports the local ecosystem. While it might not be the showiest plant in your garden, it offers the satisfaction of growing something authentic to your region. Just remember to source it responsibly and give it the well-draining conditions it craves.

If you’re passionate about native plants and want to create a landscape that truly reflects the natural beauty of the Southwest, chestnut milkvetch could be a wonderful addition to your plant palette. Sometimes the most rewarding plants are the ones that whisper rather than shout – and this quiet native has a story worth telling in your garden.

Chestnut 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 castaneiformis S. Watson - chestnut milkvetch

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