North America Native Plant

Timber Milkvetch

Botanical name: Astragalus miser var. oblongifolius

USDA symbol: ASMIO

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Astragalus decumbens (Nutt. ex Torr. & A. Gray) A. Gray var. oblongifolius (Rydb.) Cronquist (ASDEO)   

Timber Milkvetch: A Hardy Native for Western Gardens If you’re looking to add some authentic western charm to your native garden, timber milkvetch (Astragalus miser var. oblongifolius) might just be the understated beauty you’ve been searching for. This perennial native brings a touch of wild elegance to landscapes across the ...

Timber Milkvetch: A Hardy Native for Western Gardens

If you’re looking to add some authentic western charm to your native garden, timber milkvetch (Astragalus miser var. oblongifolius) might just be the understated beauty you’ve been searching for. This perennial native brings a touch of wild elegance to landscapes across the American West, though it’s definitely not your typical garden center find.

What Exactly Is Timber Milkvetch?

Timber milkvetch is a perennial member of the legume family that’s perfectly at home in the rugged landscapes of the western United States. As a variety of Astragalus miser, it represents one of nature’s many adaptations to challenging growing conditions. You might also encounter this plant listed under its synonym Astragalus decumbens var. oblongifolius in older botanical references.

Where Does It Call Home?

This hardy native has carved out its niche across six western states: Arizona, Colorado, Idaho, Nevada, Utah, and Wyoming. It’s a true child of the American West, having evolved to thrive in the region’s distinctive climate and soil conditions.

Why Consider Timber Milkvetch for Your Garden?

Here’s where timber milkvetch gets interesting for native plant enthusiasts:

  • Authentic regional character: If you’re gardening in its native range, you’re adding a plant that truly belongs to your local ecosystem
  • Low-maintenance perennial: Once established, native plants like this typically require minimal intervention
  • Drought tolerance: Like many western natives, it’s adapted to challenging water conditions
  • Wildlife connections: As a native legume, it likely provides benefits to local wildlife, though specific details aren’t well-documented

The Reality Check

Now, let’s be honest – timber milkvetch isn’t going to be your garden’s showstopper. This is a plant for serious native plant enthusiasts rather than those seeking dramatic garden displays. It’s also not readily available through typical nursery channels, so sourcing can be challenging.

Growing Timber Milkvetch Successfully

Since detailed cultivation information for this specific variety is limited, here are some general guidelines based on its native habitat and related species:

Site Selection

  • Choose a location that mimics its natural habitat – think well-draining, somewhat rocky or sandy soils
  • Full sun exposure is likely preferred
  • Avoid areas where water tends to collect

Soil Preferences

  • Well-draining soil is essential
  • Tolerates poor, rocky, or sandy soils
  • Likely prefers neutral to slightly alkaline pH

Watering and Care

  • Minimal supplemental watering once established
  • Allow soil to dry between waterings
  • Avoid overwatering, which can be fatal to desert-adapted plants

Where to Find It

Here’s the challenge: timber milkvetch isn’t something you’ll find at your local garden center. If you’re determined to grow this native, you’ll need to:

  • Contact specialized native plant nurseries in its range
  • Connect with native plant societies in Arizona, Colorado, Idaho, Nevada, Utah, or Wyoming
  • Consider seed collection from wild populations (where legally permitted and ethically appropriate)

Is Timber Milkvetch Right for You?

This plant is perfect for gardeners who:

  • Live within its native range and want to support local ecosystems
  • Enjoy the challenge of growing uncommon natives
  • Appreciate subtle beauty over flashy displays
  • Want extremely low-maintenance plants once established

However, if you’re looking for readily available plants with well-documented growing requirements and showy flowers, you might want to consider other western natives like penstemon, blanket flower, or desert marigold.

The Bottom Line

Timber milkvetch represents the kind of plant that makes native gardening both challenging and rewarding. It’s not for everyone, but for those gardening in its native range who appreciate the subtle beauty of authentic regional flora, it offers a unique connection to the local landscape. Just be prepared for some detective work in sourcing and a bit of trial and error in cultivation!

Timber 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 miser Douglas ex Hook. - timber milkvetch

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