Black Earth Rettenmund Prairie

This prairie was once rated among the top ten natural areas in Dane County in private ownership. It was used by plant ecologist John Curtis as an outdoor classroom and was one of his prairie sites in his classic book Vegetation of Wisconsin.. The University of Wisconsin-Madison herbarium has numerous entries of plants collected at this site, some dating back many years.

The preserve is in the drainage basin of, and is within site of, Black Earth Creek, one of the outstanding trout streams in southern Wisconsin.

Site stewards
Tom and Kathie Brock, 608-238-5050, email

Access & directions
From the intersection of Highways 78 and KP in Black Earth, go west on KP 1.1 miles, then south on F 0.25 mile, then west on Fesenfeld Road 0.2 mile to a small parking area south of the road. If the parking lot is occupied, park on the north side of the road. 
Map of site (see Google Maps)
Goggle Maps

Further information


Workdays are scheduled for the first Saturday morning of the month, throughout the year, except in the fall when they are held on Sunday afternoons. There may also be occasional special nonscheduled days when the need is present. However, modifications of the schedule are made if the Saturday comes on a holiday weekend. An email notification list is maintained, and those interested are invited to submit their email addresses. To get on the list, send an email to Tom Brock at [email protected] (Email addresses are never given to others.) Always call the leader before coming to a workday, as weather or other factors may make it necessary to cancel the workday.

Work day leaders:
Kathie Brock: 238-5050 ([email protected])
Willis Brown: 278-9308 ([email protected])

Prescribed burns are another major volunteer activity. Our prescribed burn is usually held at the end of March or early April. Call Tom Brock in late March at 608-238-5050 for information. Volunteers are welcome either as participants or observers.

Seed collecting is another opportuniy for volunteering. The rich flora of Black Earth Rettenmund Prairie makes seed collecting a delight. The seeds collected are planted in the Gateway Prairie and in areas of the South Unit where brush control had been carried out. Seed collecting is the principal activity in the fall work parties. In addition to regularly scheduled seed collecting days, special days are scheduled as needed.

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Usage policies

The Prairie is open to the public for hiking throughout the year. Due to the small size of the preserve, hunting is not permitted. Stay on the marked trail (see map). Access is limited to foot travel and low impact activities only.  Please clean boots and clothes before entering to help limit introduction of invasive species. 

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Description & significance

The site is one of the few remaining examples of a dry-mesic prairie in Wisconsin. In contrast to other prairie preserves in the Driftless Area, this site is on relatively level terrain. It has an outstanding assemblage of plants including several rare and uncommon species. Because of its proximity to Madison, and its easy access, the preserve has great educational value.

Black Earth Rettenmund Prairie is located on a low knob and ridge. It is characterized as dry-mesic with areas ranging from dry to nearly mesic. It harbors a rich flora of over 130 native prairie plant species. It is predominantly a forbs-rich prairie. The forbs are very diverse and include such showy species as pasque flower, lead plant, shooting star, compass plant, blazing star, purple and white prairie clover, wood lily, wood betony, false toadflax, butterfly milkweed, coneflower, black-eyed Susan, sunflowers, asters, and goldenrods. Of significance is the occurrence of pomme-de-prairie (Pediomelum esculentum), white camas lily(Zigadenus glaucus),Carex richardsonii, rough-stemmed false foxglove (Agalinis gattingeri), and a rare aster hybrid. At one time there was Hill's thistle (Cirsium hilli) but this has not been seen recently. Grasses are dominated by big and little blue stem, Indian grass, needle grass, and prairie dropseed.

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Ownership history

The preserve was once part of the William Rettenmund farm but it was probably never plowed. The owner, William Rettenmund, preserved this prairie for over 40 years. Mr. Rettenmund granted conservationists permission to study the prairie and to conduct management activities, including controlled burns. The first plant survey was done in 1969. However, Mr. Rettenmund had observed the marked "decline" in the prairie during his ownership and both he and his wife had a genuine interest in seeing it preserved and managed. It was because of Mr. Rettenmund's deep concern in seeing the prairie preserved that he sold the land to the Nature Conservancy at below market value.

Initial contact with Mr. and Mrs. Rettenmund was made by the State Natural Areas office in 1981, and serious discussions about purchase were made in 1984. At that time, about half of the site had been taken over by shrubs, aspen, and other trees. The property was acquired by the Nature Conservancy in 1986, using funds provided by Madison Audubon Society. Later the same year it was dedicated as a State Natural Area, insuring its continued protection.

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Soon after acquisition, restoration work was undertaken by the Nature Conservancy. Controlled burns were carried out at regular intervals. Hand pulling of weeds and cutting of aspen, sumac, honeysuckle, and buckthorn was carried out. Trees along the perimeter of the preserve were cut and the stumps treated with Garlon 4. Cherry trees, honeysuckle, and buckthorn on neighboring land have also been cut with the owners permission. The fence along the neighbor's pasture running east-west was rebuilt by the Nature Conservancy.

In the late 1990s, modest volunteer work parties were carried out, once or twice a year. These involved primarily brush clearing, with herbicide treatment. However, these minimal volunteer activities were insufficient to control woody growth. By the end of the 1990s, brush and tree growth on the south part of the preserve had become excessive, and prairie vegetation was being crowded out. Work on this end of the preserve was initiated again in 2000. Using support from the Savanna Oak Foundation, Inc., private contractors were hired to cut and treat vegetation. Between this work, monthly volunteer work parties, and annual controlled burns, prairie vegetation responded well and thrives.

Management Activities by the Prairie Enthusiasts

Beginning in 2003, management was taken over by the Prairie Enthusiasts under an agreement with the Nature Conservancy. At this time, more intensive restoration work was undertaken, under the guidance of Kathie and Tom Brock and with financial support from the Savanna Oak Foundation, Inc. Ownership (title) to the Prairie was transferred by the Nature Conservancy to the Prairie Enthusiasts in August 2007.

White sweet clover (Melilotus alba) remains the most serious problem. Its seeds are able to remain viable in the soil for many years. It is a peculiar characteristic of prescribed burns that fire actually "stimulates" seed germination. Thus, burns without associated sweet clover control will exacerbate the problem. It is probably for this reason that sweet clover has been historically widespread throughout the preserve.

Initially sweet clover infestations were so heavy that they had to be mowed, with hand pulling of any outliers. Prairie Enthusiasts workdays were held throughout the sweet clover season(June-August), with additional weekly workdays on Friday evenings in July. Since 2006 only hand pulling has been needed, but as much as 300 worker-hours (both volunteers and paid contractors) have been needed to control the problem. Summer workdays are scheduled by the Prairie Enthusiasts as needed.

Extensive brush controlover the past 25 years has reduced the woody vegetation problem to a lower level. The principal problem at present is smooth sumac, and continual work by volunteers and paid employees is effective. The goal is complete eradication of this seriously invasive plant.

An annual controlled burn is carried out by the Prairie Enthusiasts, usually in late March or early April. The preserve has been divided into three burn units (north, saddle, south). The saddle is burned on alternate years, together with either the north or south unit.

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  • Karen Ecklund
    commented 2022-06-29 16:34:36 -0500
    What species of milkweed besides common and butterfly am I seeing here? The leaves are smaller than the common and the flower bud clusters are pointing down. Thanks! Karen