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Bernheim

Horticulture & Sustainable Landscapes

Big Prairie

The Arboretum’s Wildness

 

The Big Prairie is one of Bernheim’s most dynamic ecosystems, a 36-acre stretch of native grasses and open sky that hums with life! Once a simple, mowed lawn, this regenerated landscape now reflects the rare grasslands that have nearly vanished from Kentucky and offers essential habitat for pollinators, grassland birds, small mammals, and uncommon plant species.

The Big Prairie stands as living proof of Bernheim’s commitment to restoring wild places—one resilient grass blade at a time.

History of the Big Prairie

A Landscape Reimagined

Long before it became a signature grassland, the Big Prairie served as cropland when Isaac W. Bernheim purchased the property in 1928. By the 1950s, it transformed into the “Great Lawn,” a manicured fescue expanse modeled after European landscapes. While open and orderly, it offered limited habitat and biodiversity.

Ecological Renewal

Restoring the Big Prairie

By the 1990s, as native grasslands disappeared across Kentucky, Bernheim began a full ecological restoration. The first prescribed burn in 1998 set the work in motion, clearing woody encroachment, reducing invasive species, and reestablishing native prairie plants. Today, the Big Prairie thrives as a vibrant ecosystem that supports wildlife and reconnects visitors with the region’s grassland heritage.

Seasonal Sightings

Winter in the Big Prairie

Milkweed Seed Pod

Asclepias syriaca

Dry seed pods cling to their stems, releasing the last silky fluff of the season.

Field Sparrow

Spizella pusilla

A small, warm-toned sparrow often seen flitting through open grasses even in colder months.

Little Bluestem

Schizachyrium scoparium

This native grass turns copper and rust in winter, creating subtle color across the prairie.

Keeping the Prairie Wild

Stewarding a Living Grassland

Caring for a grassland this large is part science, part patience, and part knowing when to let nature do the heavy lifting. At Bernheim, the Big Prairie is managed to keep it healthy, diverse, and resilient for generations to come.

Supporting Native Growth

Fire may seem dramatic, but in a prairie, it’s a vital tool. Carefully planned prescribed burns help keep woody plants from taking over, encourage native grasses and wildflowers to grow, and create patches of open soil where new plants can take hold.

  • We never burn the entire prairie at once—no more than one-third is burned in a single year.
  • This rotation ensures birds, insects, small mammals, and other wildlife always have safe places to shelter and feed.
  • Neighboring grasslands are burned on different schedules to avoid disrupting habitat across the region.
Timing matters: Burns are scheduled carefully to help plants recover and to avoid harming sensitive species.
Controlling Invasives

One of the biggest challenges is keeping aggressive invasive plants from overwhelming the natives. The more attention we give them early on, the less time we spend fighting them later.

  • After a burn, invasive plants are treated when they reach about 4–6 inches tall—this is the most effective time to stop them.
  • Key offenders: sericea lespedeza (Lespedeza cuneata) and Asian bristlegrass (Arthraxon hispidus), plus others like crown vetch, Japanese honeysuckle, and plantain species.
  • Treatment focuses on units that were burned that year for maximum effectiveness, using targeted herbicide applications to minimize harm to native plants.
Why early action? Treating invasives when they’re small saves time, money, and habitat quality down the road.
Managing the Woody Stuff

Trees and shrubs are wonderful—just not in the middle of a prairie. Small woody sprouts can often be handled during regular invasive-plant work, while larger trees require hands-on methods.

  • Saplings under ½ inch: treated with herbicide alongside other invasive plants.
  • Woody plants under ½ inch: frequently removed naturally by prescribed burns.
  • Larger trees: removed using a cut-stump method (cut, then herbicide applied to the stump) or treated with basal-bark herbicide during winter when grasses are dormant.
  • All woody removal is scheduled outside the bird-nesting season (late April through August) to protect nesting success.
Low-impact methods: These techniques prevent regrowth while keeping disturbance minimal for the rest of the prairie.

Curating Biodiversity

The Prairie’s Inhabitants

The Big Prairie supports a remarkable mix of wildlife and plants. From pollinators flitting among wildflowers to small mammals hiding in the grasses, and from songbirds nesting overhead to predators patrolling the edges, this 36-acre grassland is alive with activity. Over 86 flowering species and 18 native grasses create the foundation for this thriving ecosystem.

Who Calls the Big Prairie Home?

Wild Residents

Pollinators

Monarch butterfly, native bees, beetles, moths, grasshoppers, and ground-nesting wasps

Small Mammals

Eastern cottontail, mice and voles, and other ground-dwellers using tall grasses for cover

Birds

Songbirds using grasslands for nesting & feeding, American Woodcock, Goldfinches, sparrows, and buntings

Herbivores

White-tailed deer (Odocoileus virginianus)

Predators

Raptors, foxes, and coyotes

Native Plants

86+ flowering species

18+ native grasses

Horticulture Updates