North America Native Plant

Purpletop Tridens

Botanical name: Tridens flavus var. flavus

USDA symbol: TRFLF

Life cycle: perennial

Habit: grass

Native status: Non-native, reproduces and persists in the wild in Canada âš˜ Native to the lower 48 states  

Synonyms: Triodia flava (L.) Smyth (TRFL7)   

Purpletop Tridens: A Graceful Native Grass for Your Garden If you’re looking to add some wild beauty to your landscape, purpletop tridens (Tridens flavus var. flavus) might just be the perfect grass for you. This charming perennial grass brings a touch of prairie magic to gardens across much of North ...

Purpletop Tridens: A Graceful Native Grass for Your Garden

If you’re looking to add some wild beauty to your landscape, purpletop tridens (Tridens flavus var. flavus) might just be the perfect grass for you. This charming perennial grass brings a touch of prairie magic to gardens across much of North America, with its delicate purple-tinged seed heads dancing in the breeze come late summer.

What Makes Purpletop Tridens Special?

Purpletop tridens is a native perennial grass that’s been quietly beautifying American landscapes for centuries. Also known by its scientific name Tridens flavus var. flavus (and formerly called Triodia flava), this grass gets its common name from the gorgeous purple hues that develop in its seed heads as the growing season progresses.

As a member of the grass family, purpletop tridens has that classic grass-like appearance you’d expect, but with a refined elegance that sets it apart from your typical lawn grass. It’s the kind of plant that makes you stop and appreciate the subtle beauty of native flora.

Where Does It Call Home?

This adaptable grass is native to the lower 48 United States and has found its way into an impressive 37 states, stretching from the Atlantic coast to the Great Plains. You’ll find purpletop tridens thriving everywhere from Alabama and Florida up to Minnesota and New Hampshire, and west to states like Kansas, Oklahoma, and even parts of California and New Mexico. It’s also established itself in Ontario, Canada, where it’s considered non-native but naturalized.

Why Consider Purpletop Tridens for Your Garden?

There are several compelling reasons why this native grass deserves a spot in your landscape:

  • Low maintenance: Once established, it’s remarkably drought-tolerant and requires minimal care
  • Visual interest: The purple-tinged seed heads provide beautiful late-season color and texture
  • Wildlife habitat: Provides structure and shelter for beneficial insects and small wildlife
  • Erosion control: Its root system helps stabilize soil on slopes or disturbed areas
  • Authentic native look: Perfect for prairie restorations and naturalistic garden designs

Perfect Garden Settings

Purpletop tridens shines brightest in naturalistic settings where it can show off its wild beauty. Consider incorporating it into:

  • Native plant gardens and prairie restorations
  • Rain gardens and bioswales
  • Naturalized meadow areas
  • Erosion-prone slopes and banks
  • Low-maintenance landscape borders

While it may not be the star of a formal garden bed, it’s absolutely perfect for creating that authentic, wild look that many gardeners crave.

Growing Conditions and Care

One of the best things about purpletop tridens is how easy-going it is. This grass thrives in USDA hardiness zones 4 through 9, making it suitable for a wide range of climates.

Light requirements: Full sun is preferred, though it can tolerate some light shade

Soil needs: Adaptable to various soil types, from sandy to clay, and tolerates both wet and dry conditions once established

Water requirements: Drought-tolerant after the first year, though regular watering during establishment helps ensure success

Planting and Care Tips

Getting purpletop tridens established in your garden is refreshingly straightforward:

  • Timing: Plant in spring or fall for best establishment
  • Spacing: Allow adequate room for spreading, as this grass can form colonies over time
  • Watering: Water regularly the first year, then reduce as the plant becomes drought-tolerant
  • Maintenance: Cut back in late winter or early spring before new growth emerges
  • Propagation: Spreads naturally by seed and can form new colonies

A Word of Consideration

While purpletop tridens is native to most of the United States, gardeners in areas where it’s not indigenous (like parts of Canada) should consider whether local native grasses might be better choices for supporting regional ecosystems. That said, this grass isn’t known to be invasive or problematic, so it can be a reasonable option where appropriate native alternatives aren’t available.

The Bottom Line

Purpletop tridens offers gardeners a chance to embrace the subtle beauty of native grasslands without the high maintenance requirements of more demanding plants. Its graceful form, attractive seed heads, and ecological benefits make it a worthy addition to the right garden setting. Whether you’re creating a prairie restoration, establishing a rain garden, or simply want to add some authentic native character to your landscape, this charming grass might just be the perfect fit.

Purpletop Tridens

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Commelinidae

Order

Cyperales

Family

Poaceae Barnhart - Grass family

Genus

Tridens Roem. & Schult. - tridens

Species

Tridens flavus (L.) Hitchc. - purpletop tridens

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