North America Native Plant

Apache Passe Rubberweed

Botanical name: Hymenoxys ambigens var. floribunda

USDA symbol: HYAMF

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Hymenoxys microcephala (A. Gray) Bierner (HYMI10)  âš˜  Plummera floribunda A. Gray (PLFL2)   

Apache Passe Rubberweed: A Rare Arizona Native Worth Knowing About If you’ve stumbled across the name Apache Passe rubberweed (Hymenoxys ambigens var. floribunda), you’ve discovered one of Arizona’s botanical treasures – though it’s not one you’ll likely find at your local nursery anytime soon. This rare perennial forb is a ...

Rare plant alert!

Region: Conservation status by state

Status: S3?T2: 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 ⚘

Apache Passe Rubberweed: A Rare Arizona Native Worth Knowing About

If you’ve stumbled across the name Apache Passe rubberweed (Hymenoxys ambigens var. floribunda), you’ve discovered one of Arizona’s botanical treasures – though it’s not one you’ll likely find at your local nursery anytime soon. This rare perennial forb is a fascinating piece of the Southwest’s natural heritage, but its conservation status means it deserves special consideration from gardeners.

What Makes This Plant Special

Apache Passe rubberweed is a perennial forb, which simply means it’s a non-woody flowering plant that comes back year after year. As a member of the diverse rubberweed family, it shares characteristics with other Hymenoxys species but maintains its own unique identity. You might occasionally see it listed under its botanical synonyms, including Hymenoxys microcephala or Plummera floribunda, but they all refer to this same distinctive Arizona native.

Where It Calls Home

This plant is exclusively native to Arizona, making it a true regional specialty. Its limited geographic distribution contributes to its rarity and makes it particularly valuable for authentic southwestern native plant gardens.

The Rarity Factor: Why This Matters to Gardeners

Here’s where things get important: Apache Passe rubberweed has a Global Conservation Status of S3?T2, which indicates it’s a plant of conservation concern. While the exact status definition is currently undefined, this ranking suggests the plant faces some level of vulnerability. This means if you’re interested in growing this species, you’ll want to be extra mindful about sourcing.

If you’re considering adding this plant to your garden:

  • Only obtain plants or seeds from reputable native plant nurseries that practice ethical collection
  • Never collect from wild populations
  • Consider it a responsibility to help preserve this rare species through cultivation
  • Connect with local native plant societies or botanical gardens for guidance

Growing Challenges and Considerations

Unfortunately, specific growing information for Apache Passe rubberweed is quite limited, which reflects its rarity and specialized nature. As a native Arizona perennial forb, it likely shares some characteristics with other southwestern rubberweed species, suggesting it may prefer:

  • Well-draining soils typical of Arizona’s diverse landscapes
  • Full to partial sun exposure
  • Minimal supplemental watering once established
  • Rocky or sandy soil conditions

Is This Plant Right for Your Garden?

Given its rarity status and limited availability, Apache Passe rubberweed isn’t a plant for casual gardening projects. However, it could be perfect for:

  • Serious native plant enthusiasts committed to conservation
  • Botanical gardens or educational landscapes
  • Specialized Arizona native plant collections
  • Gardeners specifically working on habitat restoration projects

Alternative Options

If you’re drawn to the idea of growing rubberweed species but can’t source Apache Passe rubberweed responsibly, consider these more readily available Arizona natives:

  • Desert Marigold (Baileya multiradiata)
  • Brittlebush (Encelia farinosa)
  • Other more common Hymenoxys species
  • Arizona Blanketflower (Gaillardia pinnatifida)

The Bottom Line

Apache Passe rubberweed represents the kind of botanical diversity that makes Arizona’s flora so special. While it may not be the easiest plant to grow or find, its rarity makes it all the more precious. If you do have the opportunity to grow this species, approach it with the respect and care that any rare native plant deserves. Sometimes the most rewarding gardening experiences come from helping preserve the plants that need our help the most.

Remember: when in doubt about rare plants, always consult with local botanists, native plant societies, or university extension services. They can provide the most current information about conservation status and ethical growing practices.

Apache Passe 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