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Aristida purpurea (Purple threeawn)
Strickland, Sam C.

Aristida purpurea

Aristida purpurea Nutt.

Purple Threeawn, Purple 3-awn, Purple Three-awn, Red Threeawn

Poaceae (Grass Family)


USDA Symbol: arpu9

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

Often in large bunches, the culms and leaf blades of this grass rise 12-20 in. in height. The seedhead is narrow and nodding with lax, purplish branches. Three long, bristles occur from each flower.


From the Image Gallery

14 photo(s) available in the Image Gallery

Plant Characteristics

Duration: Annual
Habit: Grass/Grass-like
Root Type: Fibrous
Leaf Retention: Deciduous
Leaf Arrangement: Alternate
Leaf Complexity: Simple
Leaf Shape: Linear
Leaf Venation: Parallel
Fruit Type: Caryopsis
Size Notes: Low tufted culms 25-70 cm. tall.
Autumn Foliage: yes

Bloom Information

Bloom Color: Purple
Bloom Time: Apr , May , Jun , Jul , Aug , Sep , Oct


USA: AR , AZ , CA , CO , IA , ID , IL , KS , LA , MN , MT , NC , ND , NE , NM , NV , OK , OR , SC , SD , TX , UT , WA , WY
Canada: AB , SK
Native Distribution: Throughout Texas north to Utah, Colorado and Kansas, south to northern Mexico.
Native Habitat: Sun, open ground, well-drained sand, clay, loam, limestone; Overgrazed ranges, disturbed roadsides, abandoned fields.

Growing Conditions

Water Use: Low
Light Requirement: Sun
Soil Moisture: Dry
CaCO3 Tolerance: High
Drought Tolerance: High
Soil Description: Dry, rocky soils.
Conditions Comments: With a gentle breeze passing through purple three-awn inflorescences (grass flowers), a dreamer can imagine that the earth has purple hair. This low-growing prairie grass is good for erosion control on banks and provides a root matrix for many wildflower species. Purple three-awn is an early successional species.


Use Wildlife: Seldom grazed. The seeds are food for some song birds, like the Junco. The plants provide nesting materials or habitat for some fur and game animals.
Conspicuous Flowers: yes
Interesting Foliage: yes
Attracts: Butterflies
Larval Host: Skippers, Satyrs
Deer Resistant: High

Value to Beneficial Insects

Provides Nesting Materials/Structure for Native Bees

This information was provided by the Pollinator Program at The Xerces Society for Invertebrate Conservation.

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.

Mr. Smarty Plants says

Plants to stop erosion in Arizona
January 17, 2009
I'm looking for a plant to stop erosion; I have big wash outs that are starting to erode my yard so I guess I'm looking for deep rooting plants. I live south of Tucson, Arizona. If you can advise me...
view the full question and answer

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
Santa Barbara Botanic Garden - Santa Barbara, CA
Brackenridge Field Laboratory - Austin, TX
Nueces River Authority - Uvalde, TX
Native Seed Network - Corvallis, OR
Jacob's Well Natural Area - Wimberley, TX

Herbarium Specimen(s)

NPSOT 0356 Collected May 19, 1993 in Bexar County by Louise Morrell

1 specimen(s) available in the Digital Herbarium

Wildflower Center Seed Bank

LBJWC-89 Collected 2003-05-13 in Travis County by Lady Bird Johnson Wildflower Center

1 collection(s) available in the Wildflower Center Seed Bank

Additional resources

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


Record Modified: 2019-03-28
Research By: TWC Staff

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