North America Native Plant

Cusick’s Milkvetch

Botanical name: Astragalus cusickii var. flexilipes

USDA symbol: ASCUF

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Cusick’s Milkvetch: A Rare Idaho Native Worth Knowing If you’re passionate about native plants and love discovering botanical gems hiding in plain sight, Cusick’s milkvetch (Astragalus cusickii var. flexilipes) might just pique your interest. This lesser-known perennial represents one of nature’s more elusive characters – a plant that’s quietly doing ...

Cusick’s Milkvetch: A Rare Idaho Native Worth Knowing

If you’re passionate about native plants and love discovering botanical gems hiding in plain sight, Cusick’s milkvetch (Astragalus cusickii var. flexilipes) might just pique your interest. This lesser-known perennial represents one of nature’s more elusive characters – a plant that’s quietly doing its thing in Idaho’s landscapes while remaining largely unknown to most gardeners.

What Makes This Plant Special?

Cusick’s milkvetch belongs to the legume family, which means it has a superpower that many gardeners absolutely love: the ability to fix nitrogen in the soil. Like other members of the Astragalus genus, this perennial likely produces the characteristic pea-like flowers that make milkvetches so charming, though specific details about this particular variety remain somewhat mysterious in cultivation circles.

Where Does It Call Home?

This native beauty is found exclusively in Idaho, making it a true regional specialty. Its limited geographic range suggests that it has very specific habitat preferences and has evolved to thrive in particular Idaho ecosystems. For plant enthusiasts, this limited distribution makes it all the more intriguing – and potentially challenging to grow outside its natural range.

Should You Try Growing It?

Here’s where things get interesting (and a bit tricky). While Cusick’s milkvetch is undoubtedly a legitimate native plant worthy of conservation and appreciation, there’s remarkably little information available about cultivating this specific variety. This presents both an opportunity and a challenge for adventurous gardeners.

The Pros:

  • Native status means it supports local ecosystems
  • Perennial nature provides lasting garden value
  • Likely nitrogen-fixing abilities benefit soil health
  • Unique conversation starter for plant enthusiasts

The Challenges:

  • Limited availability in the nursery trade
  • Unknown specific growing requirements
  • Potentially very specialized habitat needs
  • Uncertain performance outside its native range

Growing Considerations

Without specific cultivation information for this variety, growing Cusick’s milkvetch becomes an exercise in educated guessing based on what we know about related Astragalus species. Most milkvetches prefer well-draining soils and can handle drought conditions once established – characteristics that make sense for a plant native to Idaho’s often arid conditions.

If you’re determined to try growing this plant, your best bet would be to source seeds or plants from reputable native plant societies or specialized botanical gardens, ensuring that any material comes from ethical, sustainable sources that don’t impact wild populations.

The Bottom Line

Cusick’s milkvetch represents the fascinating world of lesser-known native plants that deserve more attention from both botanists and gardeners. While it may not be the easiest plant to find or grow, its native status and unique character make it worthy of consideration for dedicated native plant enthusiasts.

If you can’t locate this particular variety, consider exploring other native Astragalus species or Idaho natives that might be more readily available. Sometimes the journey of seeking out unusual plants leads us to discover equally wonderful alternatives that are better suited to our gardens and growing conditions.

Remember, every native plant we successfully cultivate is a small victory for biodiversity and a step toward creating more resilient, locally-adapted landscapes. Even if Cusick’s milkvetch remains elusive, the quest to grow it might just lead you to your next favorite native plant discovery.

Cusick’s 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 cusickii A. Gray - Cusick's milkvetch

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