North America Native Plant

Timber Milkvetch

Botanical name: Astragalus miser var. serotinus

USDA symbol: ASMIS

Life cycle: perennial

Habit: forb

Native status: Native to Canada âš˜ Native to the lower 48 states  

Synonyms: Astragalus decumbens (Nutt. ex Torr. & A. Gray) A. Gray var. serotinus (A. Gray ex Cooper) M.E. Jones (ASDES)  âš˜  Astragalus serotinus A. Gray ex Cooper (ASSE14)   

Timber Milkvetch: A Hardy Native Gem for Northwestern Gardens If you’re looking for a tough, drought-tolerant native plant that won’t demand constant attention, timber milkvetch (Astragalus miser var. serotinus) might just be your new gardening best friend. This unassuming perennial proves that sometimes the most resilient plants make the biggest ...

Timber Milkvetch: A Hardy Native Gem for Northwestern Gardens

If you’re looking for a tough, drought-tolerant native plant that won’t demand constant attention, timber milkvetch (Astragalus miser var. serotinus) might just be your new gardening best friend. This unassuming perennial proves that sometimes the most resilient plants make the biggest impact in our landscapes.

What Makes Timber Milkvetch Special?

Timber milkvetch is a true Northwestern native, calling the regions of Alberta, British Columbia, Idaho, Montana, and Washington home. As a member of the legume family, this perennial brings both beauty and ecological benefits to your garden. Its delicate white to cream-colored flowers bloom in attractive clusters, while its silvery-green compound leaves add subtle texture throughout the growing season.

Why Your Garden (and Local Wildlife) Will Love It

Here’s where timber milkvetch really shines – it’s practically built for busy gardeners who want maximum impact with minimal fuss:

  • Drought champion: Once established, it thrives with little to no supplemental watering
  • Pollinator magnet: Native bees and other beneficial insects flock to its nectar-rich flowers
  • Soil improver: Like other legumes, it naturally fixes nitrogen in the soil
  • Low maintenance: No need for fertilizers or frequent care

Perfect Spots for Timber Milkvetch

This adaptable native works beautifully in several garden settings:

  • Rock gardens: Its compact form and drought tolerance make it ideal for rocky, well-drained spots
  • Native plant gardens: Pairs perfectly with other Northwestern natives
  • Xeriscape designs: A natural choice for water-wise landscaping
  • Naturalized areas: Great for creating low-maintenance meadow-like spaces

Growing Timber Milkvetch Successfully

Hardiness: Thrives in USDA zones 3-7, making it suitable for most Northwestern climates.

Sun and Soil: Give timber milkvetch full sun and well-drained soil for best results. It’s not picky about soil type but absolutely despises soggy conditions – think mountain meadow rather than bog garden.

Planting Tips:

  • Plant in spring or fall when temperatures are moderate
  • Space plants according to their mature spread (typically 1-2 feet apart)
  • Water regularly the first year to help establish roots
  • After establishment, water only during extended dry periods

Care and Maintenance

The beauty of timber milkvetch lies in what you don’t have to do. Skip the fertilizers – this nitrogen-fixer prefers lean soils. Avoid overwatering, which can lead to root rot. Simply deadhead spent flowers if you want to prevent self-seeding, or leave them for wildlife to enjoy the seeds.

Is Timber Milkvetch Right for Your Garden?

If you’re passionate about supporting native ecosystems, reducing water usage, and creating a low-maintenance landscape, timber milkvetch deserves serious consideration. It’s especially perfect for gardeners in the Pacific Northwest and northern Rocky Mountain regions who want to work with nature rather than against it.

While it may not have the flashy blooms of non-native ornamentals, timber milkvetch offers something more valuable: a deep connection to the local ecosystem and the satisfaction of growing a plant that truly belongs in your landscape. Sometimes the best gardening choices are the ones that feel effortless – and that’s exactly what timber milkvetch delivers.

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