North America Native Plant

Egg Milkvetch

Botanical name: Astragalus oophorus var. oophorus

USDA symbol: ASOOO2

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Egg Milkvetch: A Lesser-Known Native Gem for Western Gardens If you’re on the hunt for truly unique native plants that most gardeners have never heard of, let me introduce you to egg milkvetch (Astragalus oophorus var. oophorus). This intriguing perennial is one of those diamond in the rough native 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 ⚘

Egg Milkvetch: A Lesser-Known Native Gem for Western Gardens

If you’re on the hunt for truly unique native plants that most gardeners have never heard of, let me introduce you to egg milkvetch (Astragalus oophorus var. oophorus). This intriguing perennial is one of those diamond in the rough native species that deserves more attention from adventurous gardeners in the American West.

What Is Egg Milkvetch?

Egg milkvetch is a native perennial plant that calls California and Nevada home. As a member of the legume family, it shares kinship with more familiar plants like beans and peas, though you’d never guess it at first glance. This plant is part of the massive Astragalus genus, which includes hundreds of species commonly known as milkvetches or locoweeds.

The curious common name egg milkvetch hints at something distinctive about this particular variety, though like many lesser-known native plants, detailed information about its specific characteristics can be surprisingly hard to come by.

Where Does It Grow Wild?

This native beauty is found naturally in California and Nevada, where it has adapted to the challenging conditions of the American Southwest. In the wild, it likely inhabits areas with:

  • Well-drained, often rocky or sandy soils
  • Full sun exposure
  • Low annual rainfall
  • Temperature extremes typical of desert and semi-arid regions

Should You Grow Egg Milkvetch?

Here’s where things get interesting – and a bit challenging. As a native plant enthusiast, I’m always excited about lesser-known species like egg milkvetch. However, this particular variety falls into that frustrating category of plants we know exist but don’t know much about growing.

Reasons to consider it:

  • It’s a true native, supporting local ecosystems
  • As a legume, it likely provides nectar for native pollinators
  • Perennial nature means it comes back year after year
  • Adapted to challenging western growing conditions
  • Unique conversation starter in your garden

Reasons to proceed with caution:

  • Very limited horticultural information available
  • Uncertain availability in nurseries
  • Unknown growth habits and mature size
  • Unclear care requirements

Best Garden Settings

If you do manage to source egg milkvetch, it would likely thrive in:

  • Xeriscaping and drought-tolerant landscapes
  • Native plant gardens focused on California/Nevada species
  • Rock gardens with excellent drainage
  • Naturalized areas rather than formal flower beds

Growing Conditions and Care

While specific care information for this variety is limited, we can make educated guesses based on its native habitat and relatives:

Climate: Likely hardy in USDA zones 8-10, matching its native California and Nevada range.

Soil: Probably prefers well-draining, sandy or rocky soils. Most desert natives despise wet feet, so avoid heavy clay or consistently moist conditions.

Water: Once established, it should be quite drought-tolerant. Start with minimal supplemental watering and observe how it responds.

Sun: Full sun exposure is likely preferred, given its natural habitat.

The Reality Check

Let’s be honest – egg milkvetch is more of a plant collector’s challenge than a mainstream garden choice right now. The lack of readily available cultivation information means you’d be somewhat experimenting if you choose to grow it.

If you’re intrigued but want something more reliable, consider these better-documented native alternatives:

  • Desert lupine (Lupinus sparsiflorus) for similar flower structure
  • Fairy duster (Calliandra eriophylla) for desert adaptation
  • Chuparosa (Justicia californica) for drought tolerance

The Bottom Line

Egg milkvetch represents the fascinating world of lesser-known native plants that are waiting for dedicated gardeners to unlock their garden potential. While it’s not ready for mainstream cultivation advice, it could be perfect for the adventurous native plant enthusiast willing to experiment and observe.

If you do encounter this species, whether in the wild or through specialty native plant sources, consider it an opportunity to contribute to our collective knowledge about growing California and Nevada’s diverse native flora. Sometimes the most rewarding garden experiences come from the plants that make us work a little harder to understand them.

Egg 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 oophorus S. Watson - egg milkvetch

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