North America Native Plant

Zion Milkvetch

Botanical name: Astragalus zionis var. vigulus

USDA symbol: ASZIV

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Zion Milkvetch: A Rare Utah Native Worth Protecting Meet Zion milkvetch (Astragalus zionis var. vigulus), one of Utah’s most exclusive botanical residents. This perennial wildflower is so specialized that it calls only the Beehive State home, making it a true Utah endemic that deserves our attention and respect. Where Does ...

Rare plant alert!

Region: Conservation status by state

Status: S4?T1: Status is uncertain but is somewhere between the following rankings: Inexact rank: ⚘ Subspecies or variety is critically Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 5 or fewer occurrences or very few remaining individuals (<1,000) ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘

Zion Milkvetch: A Rare Utah Native Worth Protecting

Meet Zion milkvetch (Astragalus zionis var. vigulus), one of Utah’s most exclusive botanical residents. This perennial wildflower is so specialized that it calls only the Beehive State home, making it a true Utah endemic that deserves our attention and respect.

Where Does Zion Milkvetch Call Home?

This remarkable plant has chosen Utah as its one and only home base. You won’t find Zion milkvetch growing wild anywhere else in the world – it’s that picky about its neighborhood! The plant is native to the lower 48 states, but its distribution is incredibly limited within Utah’s unique landscapes.

A Plant with Serious Rarity Status

Here’s where things get serious: Zion milkvetch has a Global Conservation Status of S4?T1, which signals that this plant is quite rare and potentially at risk. This isn’t your garden-variety wildflower – it’s a botanical treasure that needs our protection.

What does this mean for gardeners? If you’re considering adding this plant to your landscape, proceed with extreme caution. Only source material that has been responsibly propagated, never collected from wild populations. Better yet, consider supporting conservation efforts for this species rather than attempting to grow it.

Why Zion Milkvetch Matters

As a member of the legume family, Zion milkvetch likely shares some beneficial traits with its Astragalus cousins. Many plants in this genus are known to:

  • Fix nitrogen in the soil, improving soil health
  • Provide nectar for native pollinators
  • Offer seeds for wildlife
  • Contribute to the unique character of Utah’s native plant communities

Growing Conditions and Care

While specific growing information for this variety is limited due to its rarity, most Astragalus species prefer:

  • Full sun exposure
  • Well-draining soils
  • Low water requirements once established
  • Minimal soil amendments

Given its Utah origins, Zion milkvetch likely thrives in arid conditions and may be suitable for USDA hardiness zones typical of Utah’s climate ranges.

A Word of Caution

Before you get too excited about adding this rare beauty to your garden, remember that its scarcity makes it unsuitable for casual cultivation. Instead of seeking out this rare species, consider these more common Utah natives that can give you similar benefits:

  • Other Astragalus species that are more common
  • Native legumes like lupines
  • Utah’s abundant wildflower species that are easier to source responsibly

The Bottom Line

Zion milkvetch represents the kind of botanical specialization that makes Utah’s flora so fascinating. While it’s tempting to want to grow every cool native plant we discover, sometimes the best way to appreciate a species is to admire it from afar and support its conservation in the wild.

If you’re passionate about Utah natives, focus your gardening energy on more readily available species while supporting organizations working to protect rare plants like Zion milkvetch in their natural habitats. That’s how we can all be part of preserving Utah’s unique botanical heritage for future generations.

Zion 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 zionis M.E. Jones - Zion milkvetch

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