Hoffman Prairie State Preserve

Hoffman Prairie is a 36-acre preserve featuring a prairie pothole—a shallow marsh surrounded by native tallgrass prairie. It is located two miles west of Clear Lake in Cerro Gordo County. The Nature Conservancy purchased the property from Larry Hoffman in 1985. It was dedicated as a biological and geological state preserve in 1986. Ownership and management was transferred to the Iowa Department of Natural Resources in 2023.

About the Land

Hoffman Prairie is located in the Des Moines Lobe landform region, and owes its origins to glacial advances into north-central Iowa about 13,000 years ago. The small marshes contained in the depressions on this preserve are surrounded by knobby terrain with numerous glacial erratics, all characteristic of the Bemis and Altamont glacial moraines of this landform region. 

Directions

1. From the intersection of I35 and Highway 18 in Clear Lake, take Highway 18 west for 5 miles to Balsam Avenue, just west of the preserve (sign: Hoffman Prairie). 
2. Turn north (right) and park on the roadside. 
3. Walk east into the preserve.

Flora

Wetlands:

• Dominant Vegetation: Cattail-dominated wetlands.
• Spring Flowers: Yellow hoary puccoon, marsh marigold, yellow stargrass, and golden alexanders; violet bird’s-foot violet and wood sorrel; white pussytoes and thimbleweed; pink prairie smoke and prairie phlox.

Uplands:

• Dominant Vegetation: Big bluestem.
• Spring Flowers: Butterfly weed, swamp milkweed, leadplant, marsh bellflower, Indian paintbrush, bastard toadflax, prairie coreopsis, prairie larkspur, showy tick-trefoil, pale purple coneflower, rattlesnake master, blue flag iris, wood lily, compass plant, nodding ladies’-tresses, and white camass.
• Fall Flowers: Prairie blazing star, rough blazing star, sky-blue aster, smooth aster, side-flowered aster, Riddell’s goldenrod, showy goldenrod, bottle gentian, and downy gentian.
• Grasses and Other Plants: Prairie dropseed, Junegrass, porcupine grass, bulrushes, sedges, and cattails.

Fauna

Butterflies:

• Marsh Species: Black dash, dion skipper, and broad-winged skipper.
• Upland Species: Poweshiek skipperling and Arogos skipper.

Birds: 

• Bobolink, yellow-headed blackbird, blue-winged teal, mallard, sedge wren, dickcissel, and red-winged blackbird.

Regulations

Hunting is not allowed.

Nearby Natural Areas

Other natural areas in the vicinity include:

• Union Hills Wildlife Area 
• Pilot Knob State Preserve