North America Native Plant

Violet Milkvetch

Botanical name: Astragalus iodopetalus

USDA symbol: ASIO2

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Violet Milkvetch: A Rare Gem for the Adventurous Native Gardener Meet violet milkvetch (Astragalus iodopetalus), a charming but elusive perennial that’s caught the attention of native plant enthusiasts across the American Southwest. This little-known member of the legume family offers a unique opportunity for gardeners who want to grow something ...

Rare plant alert!

Region: Conservation status by state

Status: S2: Status is uncertain but is somewhere between the following rankings: Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘

Violet Milkvetch: A Rare Gem for the Adventurous Native Gardener

Meet violet milkvetch (Astragalus iodopetalus), a charming but elusive perennial that’s caught the attention of native plant enthusiasts across the American Southwest. This little-known member of the legume family offers a unique opportunity for gardeners who want to grow something truly special – though it comes with some important considerations.

What Makes Violet Milkvetch Special?

Violet milkvetch is a native perennial that calls Colorado and New Mexico home. As its common name suggests, this plant produces lovely purple flowers that add a splash of color to the high desert landscape. Like other members of the Astragalus genus, it’s a legume, which means it has the remarkable ability to fix nitrogen in the soil – a natural soil improvement service that benefits neighboring plants.

This species is found exclusively in Colorado and New Mexico, making it a true regional treasure for gardeners in these areas.

A Word of Caution: This Plant is Rare

Before we dive into growing tips, there’s something crucial you need to know: violet milkvetch has a Global Conservation Status of S2, meaning it’s considered Imperiled. With typically only 6 to 20 occurrences and fewer than 1,000 to 3,000 individuals remaining in the wild, this species is extremely vulnerable.

If you’re interested in growing violet milkvetch, please only use responsibly sourced material from reputable native plant nurseries or seed suppliers who can verify their collection methods don’t harm wild populations.

Garden Appeal and Uses

Despite its rarity, violet milkvetch can be a wonderful addition to the right garden setting:

  • Native plant gardens: Perfect for gardeners focused on regional flora
  • Rock gardens: Its compact growth works well among stones and boulders
  • Xeriscapes: Drought tolerance makes it suitable for water-wise landscaping
  • Naturalized areas: Ideal for creating authentic high desert plant communities

Growing Conditions and Care

Violet milkvetch thrives in conditions that mimic its native high desert habitat:

  • Sunlight: Full sun to partial shade
  • Soil: Well-drained soils are essential – this plant doesn’t tolerate wet feet
  • Water: Drought tolerant once established, requiring minimal supplemental watering
  • Climate: Hardy in USDA zones 4-8, handling both cold winters and hot, dry summers

Planting and Propagation Tips

Growing violet milkvetch from seed can be challenging but rewarding:

  • Seeds may require scarification (light scratching of the seed coat) to improve germination
  • Plant in fall or early spring when natural moisture is more available
  • Be patient – establishment can be slow, but the wait is worth it
  • Avoid overwatering, which can lead to root rot

Benefits to Wildlife and Pollinators

Like many native legumes, violet milkvetch provides valuable ecosystem services:

  • Purple flowers attract native bees and other pollinators
  • Nitrogen fixation improves soil health for surrounding plants
  • Provides habitat and food sources for specialized native insects

Should You Grow Violet Milkvetch?

Violet milkvetch is ideal for:

  • Experienced native plant gardeners in Colorado or New Mexico
  • Those committed to conservation and using responsibly sourced plants
  • Gardeners with appropriate dry, well-drained growing conditions
  • Plant enthusiasts who appreciate rare and unique species

However, it may not be the best choice if you’re new to native gardening or don’t have the patience for slow-establishing plants.

The Bottom Line

Violet milkvetch represents both an opportunity and a responsibility. By choosing to grow this imperiled species with responsibly sourced material, you’re not just adding a unique plant to your garden – you’re participating in conservation efforts for one of the Southwest’s rarest wildflowers. Just remember: with great botanical beauty comes great conservation responsibility!

Violet 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 iodopetalus (Rydb.) Barneby - violet milkvetch

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