Diarrhena obovata

Fall Color
Species Native to Missouri
Common Name: American beakgrain 
Type: Ornamental grass
Family: Poaceae
Native Range: United States, Canada
Zone: 4 to 8
Height: 2.00 to 3.00 feet
Spread: 2.00 to 3.00 feet
Bloom Time: June to October
Bloom Description: Green with yellow anthers
Sun: Part shade to full shade
Water: Medium to wet
Maintenance: Low
Suggested Use: Naturalize
Flower: Insignificant
Tolerate: Black Walnut, Air Pollution


Easily grown in average, medium to wet soils in part shade to full shade. Prefers moist rich soils. Plants tolerate seasonal flooding. Naturalizes by slender, creeping rhizomes and can form dense colonies in optimum growing conditions.

Noteworthy Characteristics

Diarrhena obovata is a Missouri native woodland perennial grass which grows in a clump to 2-3’ tall and as wide, and typically occurs in scattered shady areas throughout the State primarily in mesic upland forests (ravines and valleys), along stream banks and at the bases and ledges of moist (often limestone) bluffs (Steyermark). This grass generally features erect to arching, shiny, narrow, bright green blades (1/4 to 3/4” wide) which gradually turn gold in fall and then tan in winter. Flowers with insignificant greenish coloring (anthers are yellowish) appear in drooping, few-flowered panicles (4-12” long) on stems rising above the foliage in mid-summer. Flowers give way to hard, brown seed heads. Each seed is tapered to a pointed beak, thus giving rise to the sometimes used common names of beak grass or obovate beakgrain. This grass is perhaps most distinctive in late summer/early fall when the beaked grains are present. Diarrhena obovata is synonymous with and was once designated as Diarrhena americana var. obovata (Gleason 1952). More recent testing conducted by Brandenburg and others (1991) reveals that the two plants merit separate species status. Differences are very technical. Steyermark maintains that D. obovata has (1) elliptic-obovate lemmas (5-7 mm long) that are rounded at the tip and short-awned, (2) fruits (1.8-2.5 mm wide) that are narrowed abruptly to a pointed beak, and (3) leaf sheaths that are usually glabrous, whereas D. americana has (1) ovate lemmas (7-10 mm long) that are tapered gradually to a pointed or short-awned tip, (2) fruits (1.3-1.8 mm wide) that are tapered to a blunt beak and (3) leaf sheaths that are often hairy. Although the native ranges of these grasses overlap, D. obovata is most commonly found from Ohio west to the Great Plains and D. americana is most commonly found from Ohio to the east coast and south to Tennessee. See Diarrhena americana.

Genus name comes from the Greek words dis meaning twice and arren meaning male in reference to each flower having two stamens.

Specific epithet is in reference to the egg-shaped grains.


No serious insect or disease problems.


A tough, spreading, ornamental grass for shady areas. Mass in woodland areas, shade gardens, slopes, pond margins, naturalized areas or native plant gardens.