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prairie Junegrass

Koeleria macrantha · Poaceae

prairie Junegrass (Koeleria macrantha)
Photo: no rights reserved · CC0 · via iNaturalist

prairie Junegrass (Koeleria macrantha) is a perennial grass or grass-like plant in the Poaceae family. It is native to North America. USDA records it as hardy in zone 3 and warmer, down to about -38°F.

At a glance

Typegraminoid USDA
Lifecycleperennial USDA
Native statusnative USDA
Mature height1.5 ft USDA
Lightshade USDA
Water needhigh USDA
Growth raterapid USDA
Soil pH6–8 USDA
BloomMay–June USDA
Flower colorYellow USDA
Hardiness zones3 and warmer USDA
Guild layerground-cover Derived
Nursery availabilityRoutinely Available USDA

USDA quoted from the USDA PLANTS database · Derived computed by a fixed rule from those columns. No value on this page is estimated.

Growing conditions

It tolerates full shade. USDA rates it as having needs consistently moist ground. Its drought tolerance is rated high. It will not tolerate waterlogged soil — USDA rates its anaerobic tolerance as none. It is recorded on soils from pH 6 to 8 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 3.

Size and growth

At maturity it reaches about 1.5 ft, making it about knee height. It grows quickly.

Bloom period

USDA records a bloom period of May through June. Flowers are yellow.

A flowering date, not a pollinator rating.

Foliage, flower and season

Summer foliage is green, fine in texture. Its flowers are not conspicuous — a plant for form and foliage. Its active growth period is spring and fall. USDA rates its lifespan as short, so plan on replacing or resowing it rather than treating it as permanent structure.

What the site needs to provide

USDA records it across sites receiving 14 to 20 inches of annual precipitation. The low end of that band is genuinely arid, so it has a wide tolerance for dry country. It needs at least 150 frost-free days to finish its season. It roots to at least 20 inches. Fertility requirement: medium.

Propagating it

Seed is the only propagation method USDA lists. Division and cuttings are not listed as options. USDA records no cold-stratification requirement, so seed should germinate without a chilling period. Its seed spreads at a slow rate. It does not spread vegetatively, so it will stay where you put it.

Resilience and wildlife

Browsing animals find it moderately palatable, so expect deer and rabbits to take an interest. Its fire tolerance is rated high. Its growth form is recorded as bunch.

Role in a guild

Ground cover. In a layered planting this is the lowest layer — it shades soil, holds moisture, and suppresses weeds. The layer is derived by a fixed rule from growth habit and mature height.

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Tags

deciduousdrought-tolerantsandy-soilnativeshade-tolerantfast-growingground-cover

Related plants

Similar role and hardiness

Where this data comes from

Every value on this page comes from the USDA PLANTS database record for symbol KOMA, or is computed from those values by a fixed rule. Nothing here is estimated or model-generated. Where USDA publishes no value, this page omits the claim rather than filling the gap.

Read our full data sources and methodology.

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