Koeleria macrantha
Common Name: Prairie junegrass 
Type: Ornamental grass
Family: Poaceae
Native Range: Europe, Asia, North America
Zone: 3 to 9
Height: 1.00 to 2.00 feet
Spread: 0.75 to 1.50 feet
Bloom Time: May to June
Bloom Description: Light green
Sun: Full sun
Water: Dry to medium
Maintenance: Low
Suggested Use: Naturalize
Flower: Showy
Tolerate: Drought, Dry Soil, Black Walnut, Air Pollution

Culture

Easily grown in dry to medium, well-drained soils in full sun. Thrives in rocky or gritty soils. Needs superior drainage. Tolerates drought. Avoid wet and/or heavy soils or shade. May be grown from seed which can be scattered on the ground for large plantings in fields. Will self-seed in optimum growing conditions. Junegrass grows to mature height and flowers by June, but thereafter may go dormant in hot and humid summer climates. In cool summer climates, it will usually remain attractive until fall. Plants may be short-lived. Cold hardiness depends upon the area from where the seed was harvested.

Noteworthy Characteristics

Koeleria macrantha, commonly called prairie junegrass, is a cool season, clump-forming, tufted, perennial bunch grass that is native throughout most of the contiguous U.S. except for the Southeast and parts of the Northeast. It is also found in Europe and Asia. In Missouri, it is typically found in dry prairies and open woods in the southwestern and central parts of the state (Steyermark). It typically grows in a compact, erect clump to 2’ tall. Mostly basal leaves (to 7” long) are medium to bright green, but may be tinged with gray-green. Narrow tapered inflorescences (to 5” long) appear in late spring atop flower spikes rising well above the basal foliage. Inflorescences open light green but change to silver-green as the seed heads mature.

Genus name honors German botanist and grass expert Georg Ludwig Koeler (1765-1807).

Specific epithet means large-flowered.

Problems

No significant insect or disease problems. Occasional problems include rusts, leaf spots and blights.

Garden Uses

Best for massing and naturalizing in fields or prairies where self-seeding is not a problem. Mix with other ornamental grasses. Potential for summer/fall dormancy makes this questionable for placement in conspicuous parts of borders.