North America Native Plant

Spalding’s Milkvetch

Botanical name: Astragalus spaldingii

USDA symbol: ASSP4

Life cycle: perennial

Habit: forb

Native status: Native to Canada âš˜ Native to the lower 48 states  

Spalding’s Milkvetch: A Rare Pacific Northwest Native Worth Protecting If you’re passionate about native plants and conservation, Spalding’s milkvetch (Astragalus spaldingii) might just be the perfect addition to your garden—with one important caveat. This charming perennial wildflower is a true Pacific Northwest native that deserves our attention and care, but ...

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 ⚘

Spalding’s Milkvetch: A Rare Pacific Northwest Native Worth Protecting

If you’re passionate about native plants and conservation, Spalding’s milkvetch (Astragalus spaldingii) might just be the perfect addition to your garden—with one important caveat. This charming perennial wildflower is a true Pacific Northwest native that deserves our attention and care, but its rarity means we need to be extra thoughtful about how we grow it.

What Makes Spalding’s Milkvetch Special?

Spalding’s milkvetch is a delightful perennial that brings subtle beauty to any native garden. In late spring and early summer, it produces clusters of small, cream-colored to white pea-like flowers that seem to glow against its silvery-green compound leaves. The plant has a low, somewhat spreading growth habit that makes it perfect for rock gardens and naturalized areas.

What really sets this plant apart, though, is its conservation story. As a species with a Global Conservation Status of S3S4 (meaning it’s vulnerable but not immediately threatened), every garden that grows Spalding’s milkvetch responsibly contributes to its long-term survival.

Where Does It Call Home?

This lovely milkvetch is native to a relatively small area of the Pacific Northwest, including British Columbia, Idaho, Oregon, and Washington. Its limited geographic range is part of what makes it so special—and so important to protect.

Should You Plant Spalding’s Milkvetch?

The short answer is: yes, but only if you can source it responsibly! Because of its rarity status, it’s crucial that you obtain seeds or plants from reputable native plant nurseries that use ethically collected, locally-sourced genetic material. Never collect from wild populations.

Here’s why it’s worth the extra effort to find responsibly-sourced plants:

  • Supports native pollinators, especially native bees
  • Adds unique texture and color to native plant gardens
  • Extremely drought tolerant once established
  • Contributes to conservation efforts
  • Perfect for low-maintenance landscaping

Growing Spalding’s Milkvetch Successfully

The good news is that once you find a responsible source, Spalding’s milkvetch is surprisingly easy to grow if you can meet its basic needs.

Growing Conditions:

  • Full sun exposure
  • Well-draining soils (it hates soggy feet!)
  • USDA Hardiness Zones 4-8
  • Drought tolerant once established

Planting and Care Tips:

  • Seeds require cold stratification for 30-60 days before planting
  • Plant in spring after the last frost
  • Water regularly the first year, then reduce watering significantly
  • Avoid fertilizing—like many native legumes, it fixes its own nitrogen
  • Mulch lightly to retain moisture and suppress weeds

Perfect Garden Companions

Spalding’s milkvetch shines in native plant gardens, rock gardens, and restoration projects. It pairs beautifully with other Pacific Northwest natives like lupines, penstemons, and native bunch grasses. Its low profile makes it an excellent choice for the front of borders or as groundcover in naturalized areas.

A Plant Worth Protecting

By choosing to grow Spalding’s milkvetch responsibly, you’re not just adding a beautiful native plant to your garden—you’re participating in conservation. Every responsibly-grown plant helps maintain genetic diversity and reduces pressure on wild populations.

Just remember: source responsibly, grow with care, and enjoy knowing that your garden is helping preserve a piece of Pacific Northwest natural heritage for future generations!

Spalding’s 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 spaldingii A. Gray - Spalding's milkvetch

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