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Tridens flavus (Purpletop tridens)
Smith, R.W.

Tridens flavus

Tridens flavus (L.) Hitchc.

Purpletop Tridens, Redtop Tridens, Tall Redtop Tridens, Purpletop, Redtop, Tall Redtop

Poaceae (Grass Family)


USDA Symbol: trfl2

USDA Native Status: L48 (N), CAN (I)

Tall redtop or Purple-top is a 2 1/2-7 ft. tall perennial grass with drooping branches bearing widely spaced reddish-purple spikelets. In mass, this species puts a purple top on old fields and open woods. The plant becomes brown in fall.


From the Image Gallery

5 photo(s) available in the Image Gallery

Plant Characteristics

Duration: Perennial
Habit: Grass/Grass-like
Root Type: Fibrous
Leaf Arrangement: Alternate
Leaf Complexity: Simple
Leaf Shape: Linear
Leaf Venation: Parallel
Inflorescence: Panicle
Fruit Type: Caryopsis
Size Notes: Up to about 7 feet tall.
Leaf: Green

Bloom Information

Bloom Color: Purple
Bloom Time: Aug , Sep , Oct , Nov


USA: AL , AR , CT , DC , DE , FL , GA , IA , IL , IN , KS , KY , LA , MA , MD , MI , MN , MO , MS , NC , NE , NH , NJ , NM , NY , OH , OK , PA , RI , SC , TN , TX , VA , VT , WI , WV
Native Distribution: S. NH to IL & NE, s. to Mex.
Native Habitat: Roadsides, Open woodlands

Growing Conditions

Water Use: Low
Light Requirement: Part Shade
Soil Moisture: Dry
CaCO3 Tolerance: Low
Soil Description: Dry soils. Sandy, Sandy Loam, Medium Loam, Clay Loam, Clay
Conditions Comments: During early growth it is readily consumed by livestock.


Use Ornamental: Attractive
Use Wildlife: Graze, Nesting material.
Attracts: Butterflies
Larval Host: Cross-line skipper, Broad-winged skipper, Little Glassywing skipper, Large Wood Nymph.

Butterflies and Moths of North America (BAMONA)

Common Wood Nymph
(Cercyonis pegala)

Larval Host
Learn more at BAMONA
Crossline Skipper
(Polites origenes)

Larval Host
Learn more at BAMONA
Little Glassywing
(Pompeius verna)

Larval Host
Learn more at BAMONA
Broad-winged Skipper
(Poanes viator)

Larval Host
Learn more at BAMONA

Find Seed or Plants

Order seed of this species from Native American Seed and help support the Wildflower Center.

Find seed sources for this species at the Native Seed Network.

View propagation protocol from Native Plants Network.

National Wetland Indicator Status

This information is derived from the U.S. Army Corps of Engineers National Wetland Plant List, Version 3.1 (Lichvar, R.W. 2013. The National Wetland Plant List: 2013 wetland ratings. Phytoneuron 2013-49: 1-241). Click here for map of regions.

From the National Organizations Directory

According to the species list provided by Affiliate Organizations, this plant is on display at the following locations:

Lady Bird Johnson Wildflower Center - Austin, TX
Pineywoods Native Plant Center - Nacogdoches, TX
Brackenridge Field Laboratory - Austin, TX
Native Seed Network - Corvallis, OR
Jacob's Well Natural Area - Wimberley, TX


Bibref 1186 - Field Guide to Moths of Eastern North America (2005) Covell, C.V., Jr.
Bibref 1185 - Field Guide to Western Butterflies (Peterson Field Guides) (1999) Opler, P.A. and A.B. Wright
Bibref 841 - Native Alternatives to Invasive Plants (2006) Burrell, C. C.
Bibref 1294 - The Midwestern Native Garden: Native Alternatives to Nonnative Flowers and Plants An Illustrated Guide (2011) Adelman, Charlotte and Schwartz, Bernard L.

Search More Titles in Bibliography

Additional resources

USDA: Find Tridens flavus in USDA Plants
FNA: Find Tridens flavus in the Flora of North America (if available)
Google: Search Google for Tridens flavus


Record Modified: 2015-04-16
Research By: LAL

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