North America Native Plant

Crescent Milkvetch

Botanical name: Astragalus amphioxys var. musimonum

USDA symbol: ASAMM2

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Astragalus musimonum Barneby (ASMU2)   

Crescent Milkvetch: A Charming Desert Annual for Water-Wise Gardens Looking for a native annual that thrives in hot, dry conditions? Meet the Crescent milkvetch (Astragalus amphioxys var. musimonum), a delightful little legume that brings subtle beauty to desert landscapes. This southwestern native might not be the showiest plant in your ...

Rare plant alert!

Region: Conservation status by state

Status: S5T2: Status is uncertain but is somewhere between the following rankings: Subspecies or variety is imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘ 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. ⚘

Crescent Milkvetch: A Charming Desert Annual for Water-Wise Gardens

Looking for a native annual that thrives in hot, dry conditions? Meet the Crescent milkvetch (Astragalus amphioxys var. musimonum), a delightful little legume that brings subtle beauty to desert landscapes. This southwestern native might not be the showiest plant in your garden, but it offers unique charm for gardeners who appreciate the understated elegance of desert flora.

Where Does Crescent Milkvetch Come From?

Crescent milkvetch is native to the southwestern United States, specifically calling Arizona and Nevada home. As a true desert dweller, this annual has adapted to some of the harshest growing conditions in North America, making it perfectly suited for water-wise gardening in similar climates.

What Makes This Plant Special?

As an annual legume, Crescent milkvetch completes its entire life cycle in just one growing season. Like other members of the pea family, it produces small, characteristic legume flowers that may be modest in size but pack plenty of ecological value. The plant’s low-growing habit makes it an excellent ground-level addition to desert garden designs.

You might also encounter this plant listed under its synonym, Astragalus musimonum, in some botanical references.

Should You Plant Crescent Milkvetch?

Here’s where things get interesting – and a bit cautious. Crescent milkvetch carries a conservation status that suggests it may be uncommon in the wild. While this makes it an excellent choice for supporting native biodiversity, it’s crucial to source seeds or plants responsibly.

Benefits for Your Garden

  • Pollinator support: The small flowers attract native bees and other beneficial insects
  • Water-wise: Perfect for xeriscaping and drought-tolerant gardens
  • Native authenticity: Supports local ecosystems and wildlife
  • Self-seeding: May return on its own in favorable conditions
  • Soil improvement: As a legume, it helps fix nitrogen in the soil

Where to Use Crescent Milkvetch

This plant shines in:

  • Desert and xeriscape gardens
  • Native plant landscapes
  • Rock gardens with sandy, well-draining soil
  • Areas where you want ground-level seasonal interest

Growing Conditions

Crescent milkvetch thrives in USDA hardiness zones 8-10, particularly in areas that mirror its native desert habitat:

  • Sunlight: Full sun exposure
  • Soil: Well-draining, sandy or rocky soils
  • Water: Minimal irrigation once established
  • Climate: Hot, dry conditions with low humidity

Planting and Care Tips

Growing Crescent milkvetch successfully is all about mimicking its natural desert environment:

  • Timing: Direct seed in fall for spring germination
  • Soil prep: Ensure excellent drainage – this plant hates wet feet
  • Watering: Water sparingly, if at all, once established
  • Maintenance: Minimal care required; let it complete its natural cycle

Important Sourcing Considerations

Given its conservation status, only obtain Crescent milkvetch from reputable native plant nurseries that can verify their sources. Never collect seeds or plants from wild populations. Responsible sourcing helps protect wild populations while still allowing you to enjoy this special native in your garden.

The Bottom Line

Crescent milkvetch offers desert gardeners a chance to grow something truly special – a native annual that connects your landscape to the authentic flora of the Southwest. While it may require a bit more effort to source responsibly, the ecological benefits and unique character it brings to water-wise gardens make it worth seeking out. Just remember: buy from reputable sources, provide excellent drainage, and let this charming desert dweller do what it does best in your sunny, dry garden spaces.

Crescent 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 amphioxys A. Gray - Crescent milkvetch

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