North America Native Plant

Steyermark’s Milkwort

Botanical name: Polygala rimulicola

USDA symbol: PORI

Life cycle: perennial

Habit: subshrub

Native status: Native to the lower 48 states  

Steyermark’s Milkwort: A Rare Gem Worth Protecting If you’re the type of gardener who gets excited about rare botanical treasures, Steyermark’s milkwort (Polygala rimulicola) might just capture your imagination. This little-known native wildflower is one of those special plants that makes you feel like you’ve discovered a secret when you ...

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 ⚘

Steyermark’s Milkwort: A Rare Gem Worth Protecting

If you’re the type of gardener who gets excited about rare botanical treasures, Steyermark’s milkwort (Polygala rimulicola) might just capture your imagination. This little-known native wildflower is one of those special plants that makes you feel like you’ve discovered a secret when you encounter it in the wild.

What Makes This Plant Special?

Steyermark’s milkwort is a perennial forb—essentially a non-woody flowering plant that comes back year after year. As a member of the milkwort family, it produces the characteristic small, colorful flowers that have made its relatives garden favorites for centuries. But unlike its more common cousins, this particular species has chosen to make its home in some pretty specific (and challenging) places.

Where You’ll Find It Growing Wild

This native beauty calls the southwestern United States home, specifically New Mexico and Texas. It’s not just picky about geography, though—Steyermark’s milkwort has a very particular taste in real estate. You’ll typically find it tucked into limestone cracks and rocky crevices, making a living in places where most plants would throw in the towel.

The Conservation Conversation

Here’s where things get serious: Steyermark’s milkwort is considered vulnerable, with a Global Conservation Status of S3. This means it’s rare throughout its range, with typically only 21 to 100 known populations and between 3,000 to 10,000 individual plants in existence. That’s not a lot when you think about it!

If you’re considering adding this plant to your garden, it’s crucial that you only obtain it from reputable, responsible sources that can verify the plant material wasn’t collected from wild populations. Better yet, consider supporting conservation efforts for this species instead.

Growing Conditions and Care

Should you manage to find responsibly sourced Steyermark’s milkwort, here’s what you need to know about keeping it happy:

  • Soil: Well-draining, alkaline conditions that mimic its native limestone habitat
  • Location: Rock gardens, crevice gardens, or specialized native plant collections
  • Hardiness: Likely suitable for USDA zones 7-9 based on its natural range
  • Water: Drought-tolerant once established, prefers minimal supplemental watering

Garden Design Role

This isn’t your typical border plant or mass planting candidate. Steyermark’s milkwort is best suited for specialized gardens that celebrate rare natives or rock garden collections. Think of it as a conversation piece—the plant equivalent of a rare first edition book that you’re thrilled to own but handle with extra care.

Wildlife and Pollinator Value

While specific research on this species’ wildlife benefits is limited, members of the milkwort family typically attract small native bees, flies, and other tiny pollinators. In its native habitat, it likely plays a role in supporting specialized pollinator communities adapted to limestone cliff ecosystems.

Should You Grow It?

The honest answer? Unless you’re a serious collector of rare natives with the proper expertise and ethical sourcing, probably not. This plant’s rarity means it’s better left to conservation professionals and specialized botanical gardens.

Instead, consider these more common native alternatives that offer similar benefits:

  • Purple milkwort (Polygala sanguinea)
  • White milkwort (Polygala alba)
  • Other regional native wildflowers suited to your specific area

The Bigger Picture

Steyermark’s milkwort reminds us why protecting native plant habitats is so important. Every limestone crevice and rocky outcrop in Texas and New Mexico could be home to one of the few remaining populations of this vulnerable species. By choosing common natives for our gardens and supporting habitat conservation, we help ensure that rare gems like this one continue to exist for future generations to discover and admire.

Sometimes the best way to appreciate a rare plant is to learn about it, advocate for its protection, and choose more common natives that won’t put additional pressure on vulnerable wild populations. That’s gardening with a conscience—and it’s pretty beautiful too.

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