North America Native Plant

Sleeping Ute Milkvetch

Botanical name: Astragalus tortipes

USDA symbol: ASTO9

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Sleeping Ute Milkvetch: A Rare Colorado Treasure Worth Protecting Meet the sleeping Ute milkvetch (Astragalus tortipes), one of Colorado’s most precious botanical gems. This little-known wildflower might not win any popularity contests, but for dedicated native plant enthusiasts and conservation-minded gardeners, it represents something truly special—a chance to help preserve ...

Rare plant alert!

Region: Conservation status by state

Status: S1: Status is uncertain but is somewhere between the following rankings: Critically Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 5 or fewer occurrences or very few remaining individuals (<1,000) ⚘

Sleeping Ute Milkvetch: A Rare Colorado Treasure Worth Protecting

Meet the sleeping Ute milkvetch (Astragalus tortipes), one of Colorado’s most precious botanical gems. This little-known wildflower might not win any popularity contests, but for dedicated native plant enthusiasts and conservation-minded gardeners, it represents something truly special—a chance to help preserve a piece of Colorado’s natural heritage right in your own backyard.

A Plant on the Edge

Before we dive into growing tips, let’s talk about why this plant deserves your attention and respect. The sleeping Ute milkvetch carries a Global Conservation Status of S1, which means it’s critically imperiled. With typically fewer than five known occurrences and less than 1,000 individuals remaining in the wild, this perennial is hanging on by a thread. When you choose to grow this plant, you’re not just adding another species to your garden—you’re participating in conservation.

Where to Find This Rocky Mountain Rarity

This Colorado endemic calls the Four Corners region home, where it has adapted to some pretty challenging conditions. You won’t find sleeping Ute milkvetch anywhere else in the world, making it a true Colorado original.

What Makes It Special

Don’t expect flashy blooms or towering heights from sleeping Ute milkvetch. This humble perennial stays low to the ground, producing delicate white to cream-colored flowers that look like tiny pea blossoms—which makes sense, since it’s part of the legume family. The silvery-green compound leaves add a subtle texture to the landscape, and the whole plant has an understated elegance that grows on you.

The Responsible Gardner’s Choice

Here’s the thing about growing rare plants: it comes with responsibility. If you’re considering adding sleeping Ute milkvetch to your garden, you absolutely must source it responsibly. This means:

  • Never collect seeds or plants from wild populations
  • Purchase only from reputable native plant nurseries that grow from ethically sourced seed
  • Consider participating in seed banking or propagation programs
  • Share seeds and plants with other conservation-minded gardeners

Growing Conditions That Make It Happy

Sleeping Ute milkvetch isn’t your typical garden plant, and it definitely isn’t for beginners. This mountain dweller has some specific needs:

  • Drainage is everything: Think desert-dry rather than mountain meadow
  • Full sun: At least 6-8 hours of direct sunlight daily
  • Alkaline soils: It prefers soils with a higher pH
  • Minimal water: Once established, it’s extremely drought-tolerant
  • Poor soils are perfect: Rich, fertile soils will actually harm this plant

USDA Hardiness and Planting Tips

This tough little plant can handle USDA hardiness zones 4-7, making it suitable for much of the mountain West and other areas with similar climates. When planting:

  • Choose a spot with excellent drainage—consider raised beds or slopes
  • Plant in spring after the last frost
  • Space plants according to nursery recommendations (exact spacing varies)
  • Water sparingly during establishment, then back off completely
  • Never fertilize—this plant thrives in nutrient-poor conditions

Garden Design Ideas

Sleeping Ute milkvetch works beautifully in:

  • Rock gardens alongside other Colorado natives
  • Xeriscaping projects that celebrate water-wise plants
  • Conservation collections focused on rare species
  • Educational gardens that tell the story of Colorado’s unique flora

Supporting Pollinators

While small, the flowers of sleeping Ute milkvetch attract native bees and other pollinators that have co-evolved with Colorado’s native plants. By growing this species, you’re supporting these important relationships that have developed over thousands of years.

The Bottom Line

Growing sleeping Ute milkvetch isn’t for every gardener, and that’s okay. This is a plant for people who are passionate about conservation, comfortable with challenging growing conditions, and committed to sourcing plants ethically. If you’re up for the challenge, you’ll be rewarded with the knowledge that you’re helping preserve one of Colorado’s rarest wildflowers for future generations.

Remember: with great rarity comes great responsibility. Choose this plant not for its showiness, but for its story—and your role in helping write the next chapter.

Sleeping Ute 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 tortipes J.L. Anderson & J.M. Porter - sleeping Ute milkvetch

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