Dichanthelium acuminatum

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Dichanthelium acuminatum (Sw.) Gould & Clark, also called tapered rosette grass, Western panicum, Western witchgrass, or Western panicgrass, is a perennial native plant of the Puget Prairie ecosystem, and it belongs to Poaceae, the grass family. Other names: Panicum occidentale.

Robert H. Mohlenbrock @ USDA-NRCS PLANTS Database / USDA SCS. 1989. Midwest wetland flora: Field office illustrated guide to plant species. Midwest National Technical Center, Lincoln.


  • Kingdom Plantae – Plants
  • Subkingdom Tracheobionta – Vascular plants
  • Superdivision Spermatophyta – Seed plants
  • Division Magnoliophyta – Flowering plants
  • Class Liliopsida – Monocotyledons
  • Subclass Commelinidae
  • Order Cyperales
  • Family Poaceae – Grass family
  • Genus Dichanthelium (Hitchc. & Chase) Gould – rosette grass
  • Species Dichanthelium acuminatum (Sw.) Gould & C.A. Clark – tapered rosette grass


Tufted perennial; stems yellowish-green, leafy towards base, spreading, usually velvety-hairy, 15-40 cm tall. Leaves flat, firm, erect to ascending, hairy, 5-10 mm wide, no auricles; ligules 3-4 mm long, consisting of long hairs. Inflorescence a panicle, open, 3-9 cm long; spikelets up to 2 mm long, short-hairy, two flowered, the lower flower sterile; glumes unequal in size; fertile lemmas hardened (Pojar and MacKinnon, 1994)

Dichanthelium acuminatum in flower. Image by Rod Gilbert

Bloom Period


Dichantheliums are characterized by two distinct blooming periods. The conspicuous primary flowering heads are terminal to the culms and are produced in late spring and early summer. Secondary flowering heads are produced from the leaf axils begininning in mid-summer and continuing into early autumn. The primary flowering heads usually have a lower seedset than the secondary ones, which have flowers that remain closed and are self pollinated. However, seeds produced by the primary flowers appear to germinate more readily than seeds from the secondary flowers.



Southern British Columbia south along the coast to California; east of the Cascades mainly along water courses or around springs in the mountains, east to Montana and Wyoming.

Dichanthelium acuminatum vegetation. Image by Rod Gilbert.


Rocky or sandy river banks or lake margins to open woods, marshy areas or dry prairies, from sea level to high elevation in the mountains. Moist, sandy ground (lakeshores, beaches, stream banks), rocky and gravelly areas in bogs, meadows and open forests at low to mid elevations (Pojar and MacKinnon, 1994).


Landscaping: Panic grass is good for a low-traffic ground cover. Useful ground cover in controlled moist area. Attractive fall/winter color. Excellent in poorly-drained locations (S. Bastin, pers. comm.).


Seed germinates readily with day temperatures of 20º C and night temperatures of 5-10º C Do not cover seeds; simply lightly press into the soil. Requires continuous moisture for germination. Good results will fall sowing - 90% germination by mid-April (S. Bastin, pers. comm.).

Conditioned seed is planted into round cell greenhouse flat liners with 38 cells per flat that have been filled with coarse processed bark and composted pine bark growing medium. Seed is surface sown at a rate of 3-5 seeds per cell and lightly covered with starter sized, 1/16" - 1/8" diameter, granite poultry grit to combat damping off diseases. Prepared flats are lightly hand watered to slightly moisten the growing medium.

Stratified seed is placed in a greenhouse maintained under natural lighting and at a minimum temperature of 70 degrees Fahrenheit. Soil moisture is maintained during germination by an automatic overhead watering system set to cycle for 20 seconds every thirty minutes during daylight hours. Germination typically occurs 7 - 10 days after placement in the greenhouse. After germination, seedlings are maintained in a greenhouse environment 2-4 months to promote development of a plug with at least 6 inches of top growth and a dense, fibrous root system suitable for mechanical transplanting. Watering is reduced to overhead hand watering once daily. Seedlings receive a water soluble complete fertilizer bi-weekly until hardening.

Hardening Phase 1 – 2 weeks.



Dichanthelium acuminatum

Abbreviation: DIAC

Seed sample from: 2011

Average Measurement: 1.6 x 1 x 0.8

Measurement Range: L: 1.5 x 1.9, W: no variation in sample set (all seeds measured 1 mm) D: 0.7 - 0.9


Shape: One side of seed has two grooves running from hilium to opposite apex that form a football shaped opening.

Color: Seeds in green and purple husk that is coarsely hairy. Inner seed is off-white with a white, slightly puckered hilium.

Surface: Seeds are glossy and smooth. Some are very finely striped longitudinally.

Latitudinal Cross Section: elliptical DIAC lat.png
Longitudinal Cross Section: elliptical DIAC long.png


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