North America Native Plant

Gladiator Milkvetch

Botanical name: Astragalus xiphoides

USDA symbol: ASXI

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Astragalus convallarius Greene var. xiphoides Barneby (ASCOX)   

Gladiator Milkvetch: A Rare Arizona Native Worth Protecting Meet the gladiator milkvetch (Astragalus xiphoides), a tough little Arizona native that’s as rare as it is resilient. This perennial legume might not be the showiest plant in the desert, but it’s got character—and a conservation story that makes it worth knowing ...

Rare plant alert!

Region: Conservation status by state

Status: S3: Status is uncertain but is somewhere between the following rankings: Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘

Gladiator Milkvetch: A Rare Arizona Native Worth Protecting

Meet the gladiator milkvetch (Astragalus xiphoides), a tough little Arizona native that’s as rare as it is resilient. This perennial legume might not be the showiest plant in the desert, but it’s got character—and a conservation story that makes it worth knowing about.

What Makes Gladiator Milkvetch Special

This Arizona endemic is what botanists call a vulnerable species, with a Global Conservation Status of S3. That means it’s found in only a limited range and faces challenges that could threaten its survival. Currently, gladiator milkvetch grows naturally only in Arizona, making it a true regional treasure.

The plant gets its dramatic common name from its sword-like characteristics, though like many milkvetches, it’s actually a relatively modest-looking perennial with compound leaves and clusters of small, pea-like flowers that typically bloom in shades of purple to pink.

Should You Grow Gladiator Milkvetch?

Here’s where things get interesting. While gladiator milkvetch would make a wonderful addition to specialized native plant gardens, its vulnerable status means you need to be thoughtful about how you acquire it.

The Conservation Angle

  • Only source plants from reputable native plant nurseries that propagate responsibly
  • Never collect from wild populations
  • Consider it for conservation gardens or educational landscapes
  • Support habitat preservation efforts in Arizona

Garden Suitability

This isn’t your typical backyard perennial. Gladiator milkvetch is best suited for:

  • Specialized native plant collections
  • Rock gardens with Arizona themes
  • Xeriscaping projects focused on rare natives
  • Botanical or educational gardens

Growing Gladiator Milkvetch Successfully

If you’re up for the challenge and can source plants responsibly, here’s what you need to know about growing this Arizona native.

Climate and Hardiness

Gladiator milkvetch is likely hardy in USDA zones 7-9, reflecting its mountain origins in Arizona. It’s adapted to the specific climate conditions of its native range, which can make it challenging to grow elsewhere.

Growing Conditions

  • Sun: Full sun exposure
  • Soil: Extremely well-draining soil is crucial
  • Water: Drought-tolerant once established; minimal supplemental watering
  • pH: Likely prefers neutral to slightly alkaline soils

Planting and Care Tips

Growing gladiator milkvetch requires attention to its specific needs:

  • Ensure excellent drainage—this plant won’t tolerate wet feet
  • Plant in spring after frost danger has passed
  • Water sparingly; overwatering is more dangerous than drought
  • Avoid fertilizing, as most native legumes prefer lean soils
  • Mulch lightly with gravel or decomposed granite rather than organic mulch

Wildlife and Pollinator Benefits

Like other members of the pea family, gladiator milkvetch likely provides valuable resources for native pollinators, particularly specialist bees that have co-evolved with Astragalus species. The flowers, though small, can be important nectar sources for native insects in their natural habitat.

The Bottom Line

Gladiator milkvetch represents the fascinating world of rare native plants that deserve our attention and protection. While it’s not the easiest plant to grow or the most widely available, it offers gardeners interested in conservation an opportunity to participate in preserving Arizona’s botanical heritage.

If you’re drawn to rare natives and specialized gardening challenges, and you can source plants responsibly, gladiator milkvetch might find a place in your collection. Just remember: with rare plants comes responsibility. Garden thoughtfully, source ethically, and help preserve these botanical treasures for future generations.

Gladiator 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 xiphoides (Barneby) Barneby - gladiator milkvetch

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