North America Native Plant

Bastard Milkvetch

Botanical name: Astragalus tegetarioides

USDA symbol: ASTE4

Life cycle: perennial

Habit: subshrub

Native status: Native to the lower 48 states  

Bastard Milkvetch: A Rare Oregon Native Worth Protecting If you’re a native plant enthusiast with a passion for rare species, you might have stumbled across the intriguing bastard milkvetch (Astragalus tegetarioides). This small but mighty Oregon native deserves a closer look – though with some important conservation considerations in mind. ...

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 ⚘

Bastard Milkvetch: A Rare Oregon Native Worth Protecting

If you’re a native plant enthusiast with a passion for rare species, you might have stumbled across the intriguing bastard milkvetch (Astragalus tegetarioides). This small but mighty Oregon native deserves a closer look – though with some important conservation considerations in mind.

What Is Bastard Milkvetch?

Bastard milkvetch is a perennial shrub that stays refreshingly compact in the garden. This low-growing beauty typically reaches just 1.5 feet tall and never exceeds 3 feet at maturity, making it perfect for smaller spaces or as an understory plant. As a member of the legume family, it shares the classic pea-like flowers and compound leaves that make this plant group so recognizable.

Where Does It Call Home?

This Oregon exclusive is native to the lower 48 states, but you’ll only find it naturally growing in Oregon. It’s what botanists call an endemic species – meaning it evolved in this specific region and exists nowhere else in the world naturally.

The Rarity Factor: Handle with Care

Here’s where things get serious. Bastard 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 in the wild, this plant is walking a conservation tightrope. It’s rare either because it’s naturally uncommon throughout its range or grows only in very specific, restricted areas.

What does this mean for gardeners? If you’re interested in growing bastard milkvetch, you absolutely must source it responsibly. Never collect from wild populations, and only purchase from reputable native plant nurseries that propagate their own stock from ethically sourced seeds.

Garden Appeal and Landscape Role

Despite its somewhat unfortunate common name, bastard milkvetch offers unique appeal for the right gardener. Its compact size makes it excellent for:

  • Rock gardens and xerophytic landscapes
  • Native plant collections and botanical gardens
  • Habitat restoration projects
  • Educational gardens focused on rare species

The plant’s legume flowers attract native bees and other pollinators, making it a valuable addition to pollinator-friendly gardens. As a nitrogen-fixing legume, it also improves soil quality for neighboring plants.

Growing Conditions and Care

Based on its Oregon origins, bastard milkvetch likely thrives in USDA hardiness zones 8-9. Like many native western plants, it probably prefers:

  • Full sun exposure
  • Well-drained, dry soils
  • Minimal water once established
  • Good air circulation

The key to success is avoiding overwatering – this drought-adapted native likely despises soggy conditions. Think Mediterranean garden rather than English cottage garden when planning its placement.

Should You Grow It?

Bastard milkvetch isn’t for every gardener. Consider growing it if you:

  • Have experience with native plants
  • Are passionate about conservation
  • Want to support rare species preservation
  • Have the right growing conditions
  • Can source it ethically

Remember, growing rare native plants comes with responsibility. You’re not just adding a pretty plant to your garden – you’re participating in conservation efforts that could help ensure this species survives for future generations.

The Bottom Line

Bastard milkvetch may not be the showiest plant in the native garden, but it offers something more valuable: a chance to connect with Oregon’s unique botanical heritage while supporting conservation efforts. If you’re up for the challenge and can source it responsibly, this rare gem could become a meaningful addition to your native plant collection.

Just remember – with great rarity comes great responsibility. Garden thoughtfully, source ethically, and help ensure that future gardeners will have the chance to grow this Oregon treasure too.

Bastard 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 tegetarioides M.E. Jones - bastard milkvetch

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