North America Native Plant

Steyermark’s Milkwort

Botanical name: Polygala rimulicola var. rimulicola

USDA symbol: PORIR

Life cycle: perennial

Habit: subshrub

Native status: Native to the lower 48 states  

Steyermark’s Milkwort: A Rare Gem of the Southwest Meet Steyermark’s milkwort (Polygala rimulicola var. rimulicola), one of nature’s most elusive botanical treasures hiding in the limestone crevices of Texas and New Mexico. This tiny perennial herb might not win any flashy garden contests, but its rarity makes it absolutely fascinating ...

Rare plant alert!

Region: Conservation status by state

Status: S3T3: 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 ⚘ Subspecies or variety is 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. ⚘

Steyermark’s Milkwort: A Rare Gem of the Southwest

Meet Steyermark’s milkwort (Polygala rimulicola var. rimulicola), one of nature’s most elusive botanical treasures hiding in the limestone crevices of Texas and New Mexico. This tiny perennial herb might not win any flashy garden contests, but its rarity makes it absolutely fascinating for native plant enthusiasts who appreciate the truly uncommon.

What Makes This Plant Special

Steyermark’s milkwort is a native perennial forb—essentially a non-woody flowering plant that comes back year after year. As a member of the milkwort family, it’s related to other Polygala species, but this particular variety has carved out an incredibly specific niche in the wild.

The plant grows naturally in just two states: New Mexico and Texas, where it clings to life in limestone rock crevices and outcrops. This isn’t your typical backyard wildflower—it’s a true habitat specialist that has evolved to thrive in conditions most plants would find impossible.

The Rarity Factor: Why You Should Think Twice

Important Conservation Note: Steyermark’s milkwort has a Global Conservation Status of S3T3, indicating it’s quite rare and potentially vulnerable. This means we need to be extremely thoughtful about how we interact with this species.

If you’re considering adding this plant to your garden, here’s what you need to know:

  • Only source plants from reputable native plant nurseries that propagate ethically
  • Never collect from wild populations
  • Consider whether your garden can truly replicate its specialized limestone habitat
  • Remember that supporting its natural habitat through conservation efforts might be more valuable than cultivation

Growing Challenges and Considerations

Let’s be honest—Steyermark’s milkwort isn’t for the average gardener. Its extreme habitat specialization means it requires very specific conditions that are difficult to replicate in typical garden settings. The plant naturally grows in limestone crevices, suggesting it needs:

  • Excellent drainage (think rock garden or crevice conditions)
  • Alkaline soil conditions from limestone
  • The specific climate conditions of its native range
  • Minimal soil depth and high mineral content

Unfortunately, detailed cultivation information for this specific variety is extremely limited, largely because so few people have successfully grown it outside its natural habitat.

Better Alternatives for Your Native Garden

If you’re drawn to the idea of growing native milkworts, consider looking into other Polygala species that are more readily available and better suited to cultivation. Many regions have their own native milkwort species that can provide similar ecological benefits without the conservation concerns.

For southwestern native gardens, focus on other regional natives that are more abundant and easier to establish, while supporting conservation efforts for rare species like Steyermark’s milkwort through habitat protection and research funding.

The Takeaway

Steyermark’s milkwort represents the incredible diversity and specialization found in our native flora. While it might not be the right choice for your home garden, learning about plants like this reminds us why protecting natural habitats is so crucial. Sometimes the best way to grow a rare plant is to ensure its wild home remains intact for future generations to discover and admire.

If you do encounter this remarkable little plant in the wild during your southwestern adventures, take a moment to appreciate its tenacity and the unique limestone world it calls home—just remember to leave it undisturbed for others to enjoy.

Steyermark’s Milkwort

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

Polygalales

Family

Polygalaceae Hoffmanns. & Link - Milkwort family

Genus

Polygala L. - polygala

Species

Polygala rimulicola Steyerm. - Steyermark's milkwort

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