North America Native Plant

Woolly Senna

Botanical name: Senna hirsuta var. glaberrima

USDA symbol: SEHIG

Life cycle: perennial

Habit: subshrub

Native status: Native to the lower 48 states  

Synonyms: Cassia leptocarpa Benth. var. glaberrima M.E. Jones (CALEG)   

Woolly Senna: A Native Southwest Treasure for Your Garden If you’re looking to add authentic Southwest character to your garden while supporting local ecosystems, woolly senna (Senna hirsuta var. glaberrima) might just be the hidden gem you’ve been searching for. This native perennial herb brings the wild beauty of the ...

Woolly Senna: A Native Southwest Treasure for Your Garden

If you’re looking to add authentic Southwest character to your garden while supporting local ecosystems, woolly senna (Senna hirsuta var. glaberrima) might just be the hidden gem you’ve been searching for. This native perennial herb brings the wild beauty of the American Southwest right to your backyard.

What Makes Woolly Senna Special?

Woolly senna is a true native of the American Southwest, calling Arizona and New Mexico home. As a perennial forb herb, it’s the kind of plant that comes back year after year without the woody stems of shrubs or trees. Think of it as nature’s way of providing reliable, low-maintenance ground coverage with authentic regional character.

You might occasionally see this plant listed under its botanical synonym, Cassia leptocarpa var. glaberrima, but don’t let that confuse you – it’s the same wonderful native plant.

Where Does Woolly Senna Grow?

This native beauty has carved out its niche in the southwestern United States, specifically thriving in Arizona and New Mexico. It’s perfectly adapted to the unique growing conditions of this region, making it an excellent choice for gardeners wanting to work with nature rather than against it.

Why Consider Woolly Senna for Your Garden?

As a native plant, woolly senna offers several compelling advantages:

  • Water-wise choice: Native plants are naturally adapted to local rainfall patterns
  • Low maintenance: Once established, native plants typically require less care than non-natives
  • Authentic regional character: Nothing beats the real deal when creating a Southwest landscape
  • Ecosystem support: Native plants provide the foundation for healthy local wildlife communities

The Reality of Growing Woolly Senna

Here’s where we need to be honest with you: woolly senna is one of those native plants that hasn’t made it into mainstream horticulture yet. While it’s a legitimate native species with real garden potential, detailed growing information and commercial availability can be challenging to find.

This doesn’t mean you should give up on it entirely! It just means you might need to:

  • Connect with local native plant societies or botanical gardens
  • Work with specialized native plant nurseries in the Southwest
  • Consider it for naturalized or wildscape areas rather than formal garden beds

Alternative Native Options

If you’re drawn to the idea of native Senna species but need something more readily available, consider exploring other native members of the Senna family that might be better documented and more widely cultivated in your area. Your local extension office or native plant society can point you toward similar natives that offer comparable benefits with better-established growing guidelines.

The Bottom Line

Woolly senna represents the kind of authentic native plant that makes Southwest gardens truly special. While it may require some detective work to source and grow successfully, plants like this are often the most rewarding for dedicated native plant enthusiasts. If you’re just starting your native plant journey, you might want to begin with more readily available natives and work your way up to rare gems like woolly senna.

Remember, every native plant we successfully cultivate and share helps preserve our natural heritage for future generations. Whether you choose woolly senna or another native alternative, you’re making a positive impact on your local ecosystem.

Woolly Senna

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Fabales

Family

Fabaceae Lindl. - Pea family

Genus

Senna Mill. - senna

Species

Senna hirsuta (L.) Irwin & Barneby - woolly senna

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