North America Native Plant

Paradox Milkvetch

Botanical name: Astragalus holmgreniorum

USDA symbol: ASHO5

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Paradox Milkvetch: A Rare Desert Gem That Needs Our Protection Meet the Paradox milkvetch (Astragalus holmgreniorum), a plant so rare and special that it lives up to its intriguing name. This little-known perennial is one of nature’s most exclusive residents, making its home in just two southwestern states and earning ...

Rare plant alert!

Region: United States

Status: S1: Status is uncertain but is somewhere between the following rankings: 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) ⚘ Endangered: In danger of extinction throughout all or a significant portion of its range. ⚘

Region: United States

Paradox Milkvetch: A Rare Desert Gem That Needs Our Protection

Meet the Paradox milkvetch (Astragalus holmgreniorum), a plant so rare and special that it lives up to its intriguing name. This little-known perennial is one of nature’s most exclusive residents, making its home in just two southwestern states and earning a spot on the endangered species list.

What Makes Paradox Milkvetch So Special?

The Paradox milkvetch belongs to the legume family, producing the characteristic pea-like flowers that make Astragalus species so recognizable. Like other milkvetches, it likely displays small purple or pink blooms that cluster along its stems, creating modest but charming displays in its native desert habitat.

Where Does It Call Home?

This remarkable plant is native to the lower 48 states, but don’t expect to find it everywhere. Paradox milkvetch has an extremely limited range, occurring only in specific locations within Arizona and Utah. Its restricted distribution is part of what makes it so precious—and so vulnerable.

A Plant in Crisis: Understanding Its Endangered Status

Important Conservation Alert: Paradox milkvetch carries a Global Conservation Status of S1, meaning it’s critically imperiled. This classification indicates extreme rarity, with typically five or fewer occurrences and very few remaining individuals (fewer than 1,000). In the United States, it’s officially listed as Endangered.

What does this mean for gardeners? This plant is fighting for survival in the wild, and every individual matters for the species’ future.

Should You Grow Paradox Milkvetch?

Here’s where we need to have an honest conversation. While the idea of growing this rare beauty might be appealing, there are several important considerations:

  • Rarity concerns: With so few plants left in the wild, any cultivation should only use responsibly sourced, legally obtained material
  • Specialized needs: This desert native likely requires very specific growing conditions that are difficult to replicate in most gardens
  • Conservation priority: Protecting existing wild populations is more important than garden cultivation

If you’re passionate about supporting this species, consider donating to conservation organizations working to protect its natural habitat instead.

Growing Conditions and Care

For those involved in legitimate conservation efforts, Paradox milkvetch likely thrives in:

  • Arid, desert-like conditions
  • Well-draining, sandy or rocky soils
  • Full sun exposure
  • Minimal water once established
  • USDA hardiness zones typical of Arizona and Utah (likely zones 4-8)

However, specific cultivation requirements remain largely unknown due to the plant’s rarity and specialized habitat needs.

Supporting Pollinators with Alternatives

While Paradox milkvetch likely provides valuable nectar for native bees and other desert pollinators, you can support similar wildlife with more common native alternatives:

  • Other Astragalus species that aren’t endangered
  • Native desert lupines
  • Local penstemon varieties
  • Regional desert marigolds

The Bottom Line

Paradox milkvetch represents both the incredible diversity of our native flora and the fragility of rare ecosystems. While it’s not a plant for typical home gardens, learning about it helps us appreciate the importance of conservation efforts. By choosing abundant native alternatives and supporting habitat protection, we can help ensure that future generations might have the chance to see this botanical paradox thriving in the wild where it belongs.

Remember: the best way to love a rare plant is sometimes to admire it from afar and work to protect its natural home.

Paradox 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 holmgreniorum Barneby - Paradox milkvetch

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