North America Native Plant

Mound Phlox

Botanical name: Phlox griseola tumulosa

USDA symbol: PHGRT

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Phlox tumulosa (Wherry) Wherry (PHTU4)   

Mound Phlox: A Rare Gem of the Great Basin Meet mound phlox (Phlox griseola tumulosa), a delightfully understated native wildflower that calls the rugged landscapes of Nevada and Utah home. This perennial forb might not be the showiest plant in your garden center, but it’s got something special that makes ...

Rare plant alert!

Region: Conservation status by state

Status: S3?T2T3: Status is uncertain but is somewhere between the following rankings: Inexact rank: ⚘ Subspecies or variety is imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘ 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. ⚘

Mound Phlox: A Rare Gem of the Great Basin

Meet mound phlox (Phlox griseola tumulosa), a delightfully understated native wildflower that calls the rugged landscapes of Nevada and Utah home. This perennial forb might not be the showiest plant in your garden center, but it’s got something special that makes it worth knowing about – it’s a true regional treasure with a story to tell.

What Makes Mound Phlox Special?

Mound phlox is what botanists call a subspecies of Phlox griseola, and it’s as native as they come to the American West. You might also see it listed under its synonym, Phlox tumulosa, in older gardening references. As a herbaceous perennial, this little forb lacks the woody stems of shrubs and trees, instead sending up fresh growth each year from its underground root system.

What really sets this plant apart is its rarity. With a conservation status that suggests some level of concern (listed as S3?T2T3), mound phlox represents the kind of specialized native plant that’s perfectly adapted to its specific environment but hasn’t spread far beyond its natural range.

Where Does Mound Phlox Grow?

This regional specialty has carved out its niche in just two states: Nevada and Utah. Within this limited range, it has adapted to the unique conditions of the Great Basin region, making it a true local native for gardeners in these areas.

Should You Grow Mound Phlox?

Here’s where things get interesting – and a bit complicated. If you’re gardening in Nevada or Utah and want to support your local native plant community, mound phlox could be a wonderful addition to your landscape. However, its rarity status means you’ll need to be extra thoughtful about sourcing.

The Responsible Route

If you’re determined to grow this native beauty, here’s what you need to know:

  • Source responsibly: Only purchase from reputable native plant nurseries that propagate their own stock rather than wild-collecting
  • Ask questions: Verify that any plants you buy were grown from legally and ethically obtained seeds or cuttings
  • Consider alternatives: Other phlox species might give you similar beauty with less conservation concern

Growing Conditions and Care

While specific cultivation information for mound phlox is limited (thanks to its rarity and specialized habitat), we can make some educated guesses based on its native range. Plants from the Nevada-Utah region typically prefer:

  • Well-draining, rocky or sandy soils
  • Full sun to partial shade
  • Low to moderate water once established
  • Protection from excessive summer humidity

As a perennial forb, mound phlox likely goes dormant during the hottest part of summer and emerges with cooler temperatures and seasonal moisture.

The Bottom Line

Mound phlox represents something special in the native plant world – a reminder that not every beautiful wildflower is meant for mass cultivation. While it’s tempting to want to grow every interesting native we encounter, sometimes the most respectful approach is to appreciate these rare plants in their natural habitat and support conservation efforts that protect their wild populations.

If you’re passionate about growing native phlox in your Great Basin garden, consider starting with more common species like desert phlox (Phlox austromontana) or long-leaf phlox (Phlox longifolia), which can give you that lovely phlox charm without the conservation concerns.

Sometimes the rarest plants teach us the most about being thoughtful gardeners and stewards of our native landscapes.

Mound 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 griseola Wherry - grayleaf phlox

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