North America Native Plant

Plateau Milkvetch

Botanical name: Astragalus serpens

USDA symbol: ASSE6

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Plateau Milkvetch: A Rare Utah Native Worth Protecting Meet the plateau milkvetch (Astragalus serpens), a little-known perennial wildflower that’s quietly holding down the fort in Utah’s high desert landscapes. This unassuming member of the legume family might not win any flashy flower contests, but it’s got something far more valuable: ...

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 ⚘

Plateau Milkvetch: A Rare Utah Native Worth Protecting

Meet the plateau milkvetch (Astragalus serpens), a little-known perennial wildflower that’s quietly holding down the fort in Utah’s high desert landscapes. This unassuming member of the legume family might not win any flashy flower contests, but it’s got something far more valuable: it’s a rare native species that plays an important role in its specialized ecosystem.

What Makes Plateau Milkvetch Special?

Plateau milkvetch is what botanists call an endemic species—meaning it’s found nowhere else in the world except Utah. This perennial wildflower has adapted to thrive in the challenging conditions of Utah’s plateau country, where many other plants simply can’t survive. As a member of the Astragalus genus (commonly known as milkvetches), it produces the characteristic pea-like flowers that legumes are famous for.

Where Does It Grow?

This rare beauty calls Utah home, specifically the plateau regions where the soil is often rocky, alkaline, and well-draining. It’s perfectly adapted to these harsh conditions that would challenge most garden-variety plants.

A Word About Rarity

Here’s where things get serious: plateau 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 isn’t a plant you’ll stumble across at your local garden center. If you’re interested in growing this species, it’s absolutely crucial to source it responsibly from reputable native plant nurseries that propagate rather than wild-collect their stock.

Should You Grow Plateau Milkvetch?

The short answer: only if you’re truly committed to conservation gardening and can source it ethically. This isn’t a plant for casual gardeners—it’s for those who understand the responsibility that comes with growing rare species.

Reasons to consider it:

  • Support conservation of a vulnerable native species
  • Add authentic Utah native character to xeriscapes
  • Attract specialized native pollinators
  • Demonstrate commitment to biodiversity preservation

Reasons to think twice:

  • Very limited availability from ethical sources
  • Specialized growing requirements
  • May not provide immediate visual impact
  • Requires understanding of conservation gardening principles

Growing Conditions and Care

If you do decide to grow plateau milkvetch, you’ll need to recreate its native Utah plateau environment:

Ideal Growing Conditions:

  • Sunlight: Full sun exposure
  • Soil: Well-draining, rocky or sandy soil with alkaline pH
  • Water: Minimal water requirements once established
  • Climate: Estimated hardy in USDA zones 4-7

Planting and Care Tips:

  • Plant in spring after last frost
  • Ensure excellent drainage to prevent root rot
  • Avoid overwatering—this plant prefers dry conditions
  • No fertilizer needed; adapted to poor soils
  • Allow natural self-seeding if conditions are right

Garden Design Role

Plateau milkvetch works best in specialized native plant gardens, rock gardens, or authentic xeriscapes designed to showcase Utah’s unique flora. It’s not a specimen plant for formal landscapes, but rather a supporting player in naturalistic designs that celebrate regional biodiversity.

Wildlife and Pollinator Benefits

Like other milkvetches, plateau milkvetch likely provides nectar for native bees and butterflies. Its flowers follow the typical legume structure that many specialized pollinators have co-evolved with, making it a valuable addition to pollinator-supporting landscapes.

The Bottom Line

Plateau milkvetch represents something increasingly rare in our world: a plant that exists nowhere else and depends on conscious conservation efforts to survive. If you’re drawn to this unique Utah native, approach it with respect, source it responsibly, and consider yourself a steward of biodiversity. For most gardeners, supporting conservation organizations or visiting this plant in its natural habitat might be more appropriate than attempting to grow it at home.

Remember, the best way to appreciate rare plants like plateau milkvetch is often to protect their wild habitats and support the organizations working to conserve them for future generations.

Plateau 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 serpens M.E. Jones - plateau milkvetch

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