North America Native Plant

Largeflower Goldenweed

Botanical name: Pyrrocoma carthamoides var. subsquarrosa

USDA symbol: PYCAS

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Haplopappus carthamoides (Hook.) A. Gray var. subsquarrosus (Greene) Dorn (HACAS)  âš˜  Pyrrocoma subsquarrosa Greene (PYSU)   

Largeflower Goldenweed: A Rare Native Treasure from the Mountain West Meet largeflower goldenweed (Pyrrocoma carthamoides var. subsquarrosa), one of those fascinating native plants that most gardeners have never heard of – and for good reason. This particular variety is something of a botanical unicorn, found only in the rugged landscapes ...

Rare plant alert!

Region: Conservation status by state

Status: S4S5T3: Status is uncertain but is somewhere between the following rankings: 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. ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘ Secure: At very low or no risk of extinction in the jurisdiction due to a very extensive range, abundant populations or occurrences, with little to no concern from declines or threats. ⚘

Largeflower Goldenweed: A Rare Native Treasure from the Mountain West

Meet largeflower goldenweed (Pyrrocoma carthamoides var. subsquarrosa), one of those fascinating native plants that most gardeners have never heard of – and for good reason. This particular variety is something of a botanical unicorn, found only in the rugged landscapes of Montana and Wyoming.

What Makes This Plant Special?

Largeflower goldenweed is a perennial forb, which is just a fancy way of saying it’s a non-woody plant that comes back year after year. Unlike shrubs or trees, forbs like this one lack significant woody tissue and keep their growing points at or below ground level – a smart survival strategy for harsh mountain climates.

This plant belongs to a group with some interesting botanical aliases. You might also see it referred to by its synonyms Haplopappus carthamoides var. subsquarrosus or Pyrrocoma subsquarrosa, depending on which botanical reference you’re consulting.

Where Does It Call Home?

This native beauty has a pretty exclusive address – you’ll only find it naturally growing in Montana and Wyoming. It’s a true child of the American West, adapted to the unique conditions of these mountain states.

Should You Plant It?

Here’s where things get tricky. Largeflower goldenweed carries a conservation status of S4S5T3, which puts it in somewhat uncertain territory regarding its rarity. While this doesn’t necessarily mean it’s endangered, it does suggest this isn’t your run-of-the-mill garden center find.

The honest truth? There’s remarkably little information available about growing this particular variety. We don’t know its preferred growing conditions, how tall it gets, what pollinators it attracts, or even what it looks like in bloom. This mystery makes it a challenging choice for most home gardeners.

If You’re Determined to Try

Should you decide to pursue this botanical enigma, here are some important considerations:

  • Source responsibly: Given its limited range and uncertain conservation status, only obtain plants or seeds from reputable native plant societies or botanical gardens
  • Respect its origins: Since it’s native to Montana and Wyoming, it likely prefers conditions similar to those regions
  • Start small: Without clear growing guidelines, consider this an experimental addition rather than a landscape cornerstone
  • Connect with experts: Reach out to native plant societies in Montana or Wyoming for guidance

Better-Known Alternatives

If you’re drawn to native goldenweeds but want something with more available information, consider looking into other Pyrrocoma species or related native wildflowers from the Asteraceae family that are better documented and more readily available.

Sometimes the most intriguing plants are the ones that keep their secrets. Largeflower goldenweed certainly falls into that category – a reminder that there’s still so much we don’t know about our native flora, even in our own backyards.

Largeflower Goldenweed

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

Asterales

Family

Asteraceae Bercht. & J. Presl - Aster family

Genus

Pyrrocoma Hook. - goldenweed

Species

Pyrrocoma carthamoides Hook. - largeflower goldenweed

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