North America Native Plant

Clearwater Phlox

Botanical name: Phlox idahonis

USDA symbol: PHID2

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Clearwater Phlox: A Rare Idaho Treasure Worth Protecting Meet Clearwater phlox (Phlox idahonis), one of Idaho’s most precious floral gems and a plant that tells a story of both beauty and conservation urgency. This delicate perennial forb represents the kind of botanical treasure that makes native plant enthusiasts’ hearts skip ...

Rare plant alert!

Region: Conservation status by state

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) ⚘

Clearwater Phlox: A Rare Idaho Treasure Worth Protecting

Meet Clearwater phlox (Phlox idahonis), one of Idaho’s most precious floral gems and a plant that tells a story of both beauty and conservation urgency. This delicate perennial forb represents the kind of botanical treasure that makes native plant enthusiasts’ hearts skip a beat—and for good reason.

What Makes Clearwater Phlox Special?

Clearwater phlox is what botanists call a forb, which is simply a fancy way of saying it’s a soft-stemmed flowering plant without woody tissue. Think of it as nature’s version of a delicate wildflower that returns year after year. This charming little plant produces small, star-shaped flowers that range from pristine white to the palest pink, creating a subtle carpet of color in late spring.

What truly sets this phlox apart isn’t just its beauty—it’s its incredible rarity and highly specialized habitat needs.

Where Does It Call Home?

Clearwater phlox is a true Idaho native, found exclusively in the Gem State. This plant has chosen some very specific real estate in north-central Idaho, particularly in the Clearwater River region that gives it its common name. It’s what we call an endemic species, meaning you won’t find it growing naturally anywhere else on Earth.

A Plant on the Edge: Understanding Its Rarity

Here’s where things get serious: Clearwater phlox has a Global Conservation Status of S1, which means it’s critically imperiled. In plain English, this plant is hanging on by a thread, with typically five or fewer known populations and fewer than 1,000 individual plants remaining in the wild. This makes it one of Idaho’s most endangered native plants.

This rarity status should give any gardener pause. While we absolutely encourage celebrating and growing native plants, Clearwater phlox requires a very thoughtful approach.

The Challenge of Growing Clearwater Phlox

Even if you could source this plant responsibly (and that’s a big if), growing Clearwater phlox presents some serious challenges:

  • Wetland requirements: This plant is classified as Facultative Wetland, meaning it usually occurs in wetlands but may occasionally venture into drier areas
  • Specialized habitat needs: It thrives in the specific conditions of Idaho’s riparian zones
  • Climate sensitivity: Adapted to Idaho’s particular climate patterns and seasonal rhythms
  • Limited hardiness range: Likely suited only for USDA zones 4-7

Our Recommendation: Admire, Don’t Cultivate

Given its critically imperiled status, we strongly recommend that home gardeners admire Clearwater phlox from afar rather than attempting to grow it. The few remaining populations need every individual plant to focus on survival and reproduction in their natural habitat, not on adapting to garden conditions.

If you’re absolutely determined to grow this species, only do so with:

  • Seeds or plants from verified, responsible sources that support conservation efforts
  • A commitment to providing specialized wetland conditions
  • Understanding that success may be limited outside its native range

Better Alternatives for Your Garden

Instead of risking harm to wild Clearwater phlox populations, consider these more common and garden-friendly phlox alternatives:

  • Wild Sweet William (Phlox divaricata): Offers similar spring blooms and easier cultivation
  • Creeping Phlox (Phlox subulata): Excellent ground cover with spectacular spring flowers
  • Prairie Phlox (Phlox pilosa): Native to many regions with beautiful pink blooms

How You Can Help

The best way to support Clearwater phlox is through conservation rather than cultivation:

  • Support organizations working to protect Idaho’s rare plants
  • Choose other native plants for your garden that don’t face extinction pressure
  • Spread awareness about the importance of protecting rare native species
  • If you’re in Idaho, report any suspected sightings to local botanists or conservation groups

Clearwater phlox reminds us that some of nature’s most beautiful creations are also its most vulnerable. By making thoughtful choices in our gardens and supporting conservation efforts, we can help ensure that future generations will still be able to marvel at this remarkable Idaho endemic in its natural home.

Clearwater Phlox

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Solanales

Family

Polemoniaceae Juss. - Phlox family

Genus

Phlox L. - phlox

Species

Phlox idahonis Wherry - Clearwater phlox

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