North America Native Plant

Silverleaf Milkvetch

Botanical name: Astragalus argophyllus var. martinii

USDA symbol: ASARM

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Astragalus argophyllus Nutt. var. pephragmenoides Barneby (ASARP2)   

Silverleaf Milkvetch: A Hardy Native Perennial for Western Gardens If you’re looking to add some authentic western charm to your garden while supporting local wildlife, silverleaf milkvetch (Astragalus argophyllus var. martinii) might just be the unsung hero your landscape needs. This native perennial brings both beauty and ecological value to ...

Silverleaf Milkvetch: A Hardy Native Perennial for Western Gardens

If you’re looking to add some authentic western charm to your garden while supporting local wildlife, silverleaf milkvetch (Astragalus argophyllus var. martinii) might just be the unsung hero your landscape needs. This native perennial brings both beauty and ecological value to gardens across the American West, though it’s definitely not your typical garden center find.

Meet the Silverleaf Milkvetch

Silverleaf milkvetch is a native perennial that belongs to the legume family, making it a natural soil improver thanks to its nitrogen-fixing abilities. You might occasionally see it listed under its synonym Astragalus argophyllus var. pephragmenoides, but don’t let the fancy botanical names intimidate you – this is a down-to-earth plant that’s perfectly adapted to western conditions.

Where You’ll Find It Growing Wild

This resilient native calls the western United States home, naturally occurring across seven states: Arizona, Colorado, Idaho, Montana, Nevada, Utah, and Wyoming. It’s particularly well-suited to the intermountain regions and thrives in the challenging conditions that define much of the American West.

Why Your Garden (and Local Wildlife) Will Love It

Here’s where silverleaf milkvetch really shines:

  • Pollinator magnet: Those charming purple to pink pea-like flowers are irresistible to native bees and other beneficial insects
  • Low maintenance: Once established, this drought-tolerant native practically takes care of itself
  • Soil improvement: As a legume, it naturally enriches your soil with nitrogen
  • Authentic western beauty: The silvery-gray foliage provides a lovely contrast in native plant gardens
  • Wildlife support: Provides food and habitat for native insects and other wildlife

Perfect Garden Situations

Silverleaf milkvetch works best in:

  • Xeric and drought-tolerant gardens
  • Native plant landscapes
  • Naturalized meadow areas
  • Wildlife habitat gardens
  • Low-maintenance landscape zones

Growing Conditions and Care

This hardy native is surprisingly adaptable, thriving in USDA hardiness zones 4-8. Here’s what it needs to flourish:

  • Sunlight: Full sun is essential for best growth and flowering
  • Soil: Well-drained soils are crucial – this plant despises wet feet
  • Water: Extremely drought tolerant once established; minimal watering needed
  • Maintenance: Very low maintenance; may benefit from occasional deadheading

The Reality Check

Let’s be honest – silverleaf milkvetch isn’t the easiest native to find at your local garden center, and it can be somewhat challenging to establish from seed. However, for dedicated native plant enthusiasts willing to seek out specialized nurseries or work with native plant societies, the effort pays off with a truly authentic piece of western American flora.

Getting Started

If you’re determined to add this native beauty to your garden:

  • Source plants or seeds from reputable native plant nurseries
  • Plant in spring after the last frost
  • Ensure excellent drainage – consider raised beds or slopes
  • Be patient during establishment; native plants often take time to settle in
  • Once established, step back and let nature take its course

Silverleaf milkvetch may not be the showiest plant in your garden, but it represents something special: a genuine connection to the natural heritage of the American West. For gardeners committed to creating authentic, sustainable landscapes that support local ecosystems, this unassuming native perennial offers both beauty and ecological integrity that’s hard to match.

Silverleaf 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 argophyllus Nutt. - silverleaf milkvetch

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