North America Native Plant

Pinaleno Mountain Rubberweed

Botanical name: Hymenoxys ambigens var. ambigens

USDA symbol: HYAMA

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Plummera ambigens S.F. Blake (PLAM)   

Pinaleno Mountain Rubberweed: A Rare Arizona Native Worth Protecting Meet one of Arizona’s most exclusive botanical residents: the Pinaleno Mountain rubberweed (Hymenoxys ambigens var. ambigens). This isn’t your typical garden center find – in fact, you’re more likely to spot a desert bighorn sheep than encounter this elusive native wildflower ...

Rare plant alert!

Region: Conservation status by state

Status: S3?T1?: Status is uncertain but is somewhere between the following rankings: Inexact rank: ⚘ Subspecies or variety is 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) ⚘ 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 ⚘

Pinaleno Mountain Rubberweed: A Rare Arizona Native Worth Protecting

Meet one of Arizona’s most exclusive botanical residents: the Pinaleno Mountain rubberweed (Hymenoxys ambigens var. ambigens). This isn’t your typical garden center find – in fact, you’re more likely to spot a desert bighorn sheep than encounter this elusive native wildflower in cultivation!

What Makes This Plant Special?

The Pinaleno Mountain rubberweed is a perennial forb, which simply means it’s a non-woody flowering plant that returns year after year. As a member of the sunflower family, it shares DNA with more familiar garden favorites like black-eyed Susans and coreopsis, but this particular variety has chosen a much more exclusive lifestyle.

Formerly known by the botanical synonym Plummera ambigens, this plant represents the incredible diversity that exists within Arizona’s native flora – much of which remains largely unknown to home gardeners.

Where Does It Call Home?

This rare beauty is endemic to Arizona, meaning it exists nowhere else on Earth. Its common name gives away its preferred real estate – the mountainous regions where elevation and climate create just the right conditions for its survival.

The Reality Check: Why You Probably Shouldn’t (and Can’t) Grow It

Here’s where we need to have an honest conversation. The Pinaleno Mountain rubberweed carries a Global Conservation Status of S3?T1?, which indicates it’s quite rare and potentially vulnerable. This isn’t a plant you’ll find at your local nursery, and that’s actually a good thing for several important reasons:

  • Its rarity means wild populations need protection, not harvesting
  • It likely has very specific growing requirements that are difficult to replicate in typical garden settings
  • Responsible sourcing would be nearly impossible for home gardeners
  • Its natural habitat conservation is more important than cultivation

What We Don’t Know (And Why That Matters)

The truth is, much about this plant remains a mystery. We don’t have detailed information about its specific growing conditions, pollinator relationships, wildlife benefits, or cultivation requirements. This knowledge gap actually tells us something important – it’s so rare and specialized that it hasn’t been extensively studied or brought into cultivation.

Better Alternatives for Your Arizona Garden

Instead of seeking out this rare gem, consider these more readily available Arizona natives that can bring similar beauty to your landscape:

  • Desert marigold (Baileya multiradiata) – a cheerful yellow bloomer
  • Brittlebush (Encelia farinosa) – drought-tolerant with bright daisy-like flowers
  • Coreopsis species native to Arizona – reliable perennial bloomers
  • Desert willow (Chilopsis linearis) – for larger spaces

How You Can Help

While you might not be able to grow Pinaleno Mountain rubberweed in your backyard, you can still support its conservation:

  • Support organizations working to protect Arizona’s rare plant habitats
  • Choose other native Arizona plants for your garden to support local ecosystems
  • Learn about and respect rare plant populations if you encounter them while hiking
  • Spread awareness about the importance of plant conservation

The Bigger Picture

The Pinaleno Mountain rubberweed reminds us that not every beautiful native plant is meant for our gardens – and that’s perfectly okay. Sometimes the best way to appreciate a rare species is to protect its wild habitat and choose more common natives for our home landscapes.

By making informed choices about which plants we grow and supporting conservation efforts for rare species like this one, we can be better stewards of our native plant heritage. After all, some treasures are worth more when left undisturbed in their natural homes.

Pinaleno Mountain Rubberweed

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

Hymenoxys Cass. - rubberweed

Species

Hymenoxys ambigens (S.F. Blake) Bierner - Pinaleno Mountain rubberweed

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