Tom's Blog

Sunday, July 10, 2016

Summer brush control at colorful Black Earth Rettenmund Prairie

Sweet clover control at Black Earth Rettenmund Prairie is almost finished for the summer, and we are returning to brush control activities. Yesterday was our monthly volunteer work party, ably managed by Kathie.

This year brush control work focuses on the South Unit, which was not burned. We burn each of the three units at Rettenmund two out of three years, so that each year one unit is unburned. This means that any woody vegetation in that unit is not killed and is larger and has the opportunity to leaf out, making it easier to find. This is important because we are having such good control of woody vegetation that the woodies are quite small and we need help finding them.

The volunteer group walked across the whole prairie on their way to the South Unit, pulling any scattered sweet clover plants that might have been missed (very few indeed!).

Cutting and treating
small woody vegetation in the South Unit
Our procedure for woodies is to hand clip each stem near the base, then spray the cut stem with 20% Garlon 4 in bark oil. Since each person is working alone (with clippers and spray bottle), all cut stems are sure to be treated. The cut stems are pulled out and thrown on a pile. Woody vegetation consists of gray dogwood, brambles (dewberry and black raspberry), grape, bittersweet, and the occasional small honeysuckle. Once in a while a sumac or small buckthorn is found, but not very often.

As the photo shows, this is "stoop" labor, but it is a delight to work in a prairie that is in such good shape.

Ten years ago this whole unit was shoulder-high with woody vegetation

Five years ago we started to eradicate a large sumac clone in this area (which we call the Narrows).
Today sumac is hard to find!

Verbena stricta now flowering on the Saddle
Typical prairie bunch grass, Andropogon gerardii, with butterfly milkweed and lead plant flowering
in the background. This grass is most frequent on the Saddle.

Monday, July 4, 2016

Prairie plant species missing at Black Earth Rettenmund Prairie

This post discusses a number of prairie plant species that "should" be at Black Earth Rettenmund Prairie but are not. This discussion is based on a review of the various floras that have been done at Black Earth Rettenmund Prairie over the past 65 years, and on observations that Kathie and I have made during the past 15 years.

See the table at the end of this post for a complete list of the prairie species known to be present.

This outstanding Wisconsin prairie remnant is one of the jewels of southern Wisconsin, whose study goes back to the work in the early 1950s by John Curtis and students. Kathie and I have been managing this prairie since 2001, and I have done historical research on the site (Brock, 2014). This prairie is characterized by its diverse prairie flora and absence from disturbance. For the past 30 years it has been extensively managed, involving major and continuous brush and invasive tree control, weed control, and prescribed burns.

Typical prairie grasses at Rettenmund are big bluestem, side oats grama, little bluestem, Indian grass, prairie dropseed, and needle grass. However, the present discussion is restricted to forbs, which are much more diverse.

Rettenmund Prairie is part of the original southern Wisconsin prairie along and near Black Earth Creek which was first delineated by the Federal land surveyors in presettlement 1832 (Section 27 of Town 8N Range 6E). All except the present 16 acres have now been converted to agriculture or urban settlement. (This 16 acres is considerably larger than the 4 acre size that Curtis and Greene (1949) decided was the minimum size a prairie could be and still be reasonably studied floristically.)

In their study of southern Wisconsin prairies, Curtis and Greene (1949) and Curtis (1959) classified prairie species, based on their natural distribution, into five categories: dry, dry-mesic, mesic, wet-mesic, and wet. Henderson (1998), using the Curtis data, followed these same categories. It should be noted that although most prairie species have an optimum habitat in one or two of the prairie types, most species are often found in the other prairie types, generally in reduced amounts. This is reflected in the Henderson data which give the percentage of prairie stands across the state in which a given species is found. Henderson’s data are derived from a computerized analysis of the Curtis data that was carried out by Umbanhowar (1992). (Computers were not available when Curtis did his analysis.) Fortunately, all of the Curtis original field data were still available to Umbanhowar.

Rettenmund Prairie is a typical dry to dry-mesic prairie with a small amount of mesic habitat. It is mostly a high knoll that sits between crop fields, but lower areas along the northern edge, and the north-facing unit itself, are more mesic in character. Only a small area in one corner has ever been cropped, and cropping ceased about 30 years ago. The former crop field was planted to prairie about 10 years ago and now has a diverse species flora, with emphasis on species the grow well in dry-mesic to mesic sites.

Although the prairie flora at Rettenmund is extensive and diverse, there are a number of species that are missing. The purpose of this post is to discuss these missing species.

It should be emphasized that no new species have ever been knowingly introduced here. Seeds have been collected here primarily for planting back at formerly brushy sites, or in other parts of Rettenmund where species enhancement was needed. Thus, as far as can be told, we have here the original native flora

The complete Rettenmund Prairie species list is given at the end of this post, with their prairie types. The following table lists species that are missing but, based on their classifications, “should” be  there. Each of these species is discussed separately below.

Species missing from Rettenmund Prairie
Curtis/Henderson classification
Aster novae-angliae
Astragalus canadensis
Baptisia alba
Baptisia bracteata
Ceanothus americanus
Desmodium canadense
Desmodium illinoense
Echincacea pallida
Heliopsis helianthoides
Lespedeza capitata
Liatris pycnostachya
Oxalis violacea
Parthenium integrifolium
Zizia aptera
Zizia aureus

 Although Aster novae-angliae is primarily a mesic to wet-mesic species, it is also found in dry habitats, often on disturbed ground, railroad ballast, roadsides and ditches, etc. It is the showiest of the asters and hence is widely used in prairie plantings. Because it is showy, it is unlikely that it would be missed in any floristic survey.

Astragalus Canadensis is common in southern Wisconsin and is found in borders, clearings, trails, roadsides, dry to mesic prairies, and other similar habitats.

Baptisia alba is a widespread prairie species which, although primarily a mesic species, is often found on drier prairies. Although found only in southern Wisconsin, it is widespread here. Also, it is widely planted in prairie restorations, where it does extremely well. There are habitats at Rettenmund where this species could thrive, but it seems not to be here.

Baptisia bracteata is also a widespread prairie species, found from dry to mesic prairies, dry lime sites, sandy and gravelly sites. A species of the prairies, it “should” be at Rettenmund, but isn’t.

Although Ceanothus americanus is often considered a savanna species, it also thrives in dry to mesic prairies, roadsides, hillsides and banks, and other similar habitats. This relative of buckthorn is actually a shrub, but where prescribed fire is frequent it never gets very large. Extensive populations of Ceanothus are present a few miles from Rettenmund at Pleasant Valley Conservancy, including some thriving native populations along County Highway F. For some reason, seeds have been unable to manage the three mile distance along Highway F.

Echinacea pallida is present as a native in a few southern Wisconsin counties but is widely distributed in other states south of here, including a wide sweep of states along the Mississippi River. Also, it is widely used in prairie plantings where it grows extremely well. Native populations are known within 20 miles of Rettenmund, yet it has not worked its way here.

Desmodium illinoiense and Desmodium canadense are prairie species that do well in dry-mesic to mesic habitats, and are widespread in Wisconsin. They both are found along roadsides and railroads. According to Cochrane and Iltis (2000) D. illinoense “…sometimes persist[s] along grassy, unshaded roadsides and railroads with mixtures of weeds and prairie or upland-thicket species.” D. canadense, being showy, is widely used in prairie restorations, where it thrives. Neither species has ever been reported from Rettenmund.

Heliopsis helianthoides (false or ox-eye sunflower) is common throughout southern and western Wisconsin, on wet to dry-mesic prairies. Because it flowers early, it is also widely used in prairie plantings, where it thrives.

Although Lespedeza capitata has never been reported at Rettenmund, it is widespread in Wisconsin and the Midwest. According to Cochrane and Iltis (2000) it is “Wisconsin’s most abundant native legume, common in dry to mesic prairies…”. According to Cochrane/Iltis, it is an active invader of roadsides, railroads, old field, and shores. It is easy to grow, is considered a bird attractant, and is often used in prairie seed mixes. Why isn’t it at Rettenmund? It has certainly become dispersed all over southern Wisconsin.

Although two other species of Liatris are common at Rettenmund, Liatris pycnostachya is not present. This species is somewhat more mesic than the other two, and may require deeper soil for establishment.

According to Cochrane and Iltis (2000), Parthenium integrifolium was once common in Wisconsin, primarily at mesic sites. Because most mesic sites have been converted to agriculture, this species is now found only on prairie remnants or on planted prairies. Since it thrives on planted prairies (including those at Pleasant Valley Conservancy) why hasn’t it become established at Rettenmund?

Oxalis violacea is widespread in the Midwest and although primarily a mesic species, it is found frequently in southern Wisconsin and is especially present on prairies, including goat prairies, prairie glades, and other open habitats. It flowers early so that it is unlikely to be missed in any floristic study.

Zizia aureus is another widespread prairie/savanna species, which although most frequently found in mesic habitats is also present in dry-mesic prairies. A single small patch of Zizia aureus was actually found at Rettenmund a few years ago, but did not return the following year. There are large amounts of Z. aureus along County F three miles from Rettenmund.

The related species Z. aptera is also primarily a mesic species but does occur in dry-mesic sites. Although not now present at Rettenmund, it was reported by Read in 1972 and by Henderson in 1988.

It should be emphasized that, based on the presence of existing species, suitable habitats exist at Rettenmund for all these missing species. Extensive mesic habitat is present on the north-facing hill of the north unit, where Phlox, Anemone canadense, Helianthus grosseserratus, and Heuchera richardsonii are currently thriving. Also, extensive areas of another mesic species, Thalictrum dasycarpum are present in the south unit.

Why are these species missing? There have certainly been enough years for them to become dispersed. All of them flourish at nearby sites, even in many cases spreading “on their own”. Were they once here in the large presettlement prairie and when this prairie was fragmented, they were cut off and disappeared?

Is the Rettenmund habitat unfavorable despite its suitability for other species, including many typical prairie species.

Is the site too small?

Are these species now dispersing to Rettenmund but are unable to compete with the already established flora?

Complete species list for Black Earth Rettenmund Prairie

Common name
Prairie type
Agalinis aspera
Rough false foxglove
Agalinis gattingeri
Round-stemmed false foxglove
Amorpha canescens****
Andropogon gerardii****
Big bluestem
Anemone canadensis
Canada anemone
Anemone cylindrica
Anemone patens
Pasque flower
Antennaria neglecta
Field pussytoes
Antennaria plantaginifolia
Plantain pusstoes
Apocynum androsaemifolium
Spreading dogbane
Apocynum cannabinum
Indian hemp
Arabis lyrata
Lyrate rock cress
Arenaria stricta
Asclepias syriaca
Common milkweed
Asclepias tuberosa
Butterfly milkweed
Asclepias verticillata
Whorled milkweed
Asclepias viridiflora
Short green milkweed
Aster ericoides
Heath aster
Aster laevis
Smooth blue aster
Aster oolentangiensis
Sky-blue aster
Aster pilosus
Frost aster
Aster sericeus****
Silky aster
Bouteloua curtipendula****
Side oats grama
Bromus kalmii
Kalm's brome
Cirsium discolor
Pasture thistle
Cirsium hillii
Hill's thistle
Comandra umbellata
False toadflax
Coreopsis palmata
Prairie tickseed
Dalea candida
White prairie clover
Dalea purpurea****
Purple prairie clover
Dodecatheon meadia
Shooting star
Erigeron strigosus
Daisy fleabane
Eryngium yuccifolium
Rattlesnake master
Euphorbia corollata****
Flowering spurge
Euthamia graminifolia
Grass-leaved goldenrod
Fragaria virginiana
Wild strawberry
Galium boreale
Northern bedstraw
Gentiana puberulenta
Prairie gentian
Gentianella quinquefolia
Stiff gentian
Geum triflorum
Prairie smoke
Helianthus grosseseratus
Saw-tooth sunflower
Helianthus occidentalis
Western sunflower
Helianthus pauciflorus
Showy sunflower
Heuchera richardsonii
Prairie alum-root
Hypoxis hirsuta
Yellow star-grass
Koeleria macrantha
June grass
Kuhnia eupatorioides
False boneset
Lactuca canadensis
Wild lettuce
Lechea stricta
Prairie pinweed
Liatris aspera
Rough blazing star
Liatris cylindracea
Dwarf blazing star
Lilium philadelphicum
Wood lily
Linum  sulcatum
Yellow flax
Lithospermum canescens
Hoary puccoon
Lobelia spicata
Pale spiked lobelia
Lythrum alatum
Winged loosestrife
Maianthemum racemosum
False Solomon's seal
Monarda fistulosa
Wild bergamot
Oenothera biennis
Panicum leibergii
Prairie panic grass
Panicum oligosanthes
Few flowered panic grass
Panicum perlongum
Long-leaved panic grass
Pedicularis canadensis
Wood betony
Pediomelum esculentum
Prairie turnip
Phlox pilosa
Prairie phlox
Physalis heterophylla
Clammy ground cherry
Physalis virginiana
Virginia ground cherry
Polygala sanguinea
Field milkwort
Polygala senega
Seneca snakeroot
Polygonatum biflorum
Solomon's seal
Potentilla argute
Prairie cinquefoil
Prenanthes racemosa
White lettuce
Pycnanthemum virginianum
Common mountain mint
Ratibida pinnata
Yellow coneflower
Rosa spp.****
Rudbeckia hirta
Black-eyed Susan
Schizacharium scoparium****
Little bluestem
Silphium integrifolium
Silphium laciniatum
Compass plant
Sisyrinchium campestre
Blue-eyed grass
Solidago canadensis
Canada goldenrod
Solidago gigantea
Late goldenrod
Solidago juncea
Early goldenrod
Solidago missouriensis
Missouri goldenrod
Solidago nemoralis
Old-field goldenrod
Solidago ptarmicoides
White goldenrod
Solidago rigida****
Stiff goldenrod
Solidago speciosa
Showy goldenrod
Sorghastrum nutans
Indian grass
Spiraea alba
Spiranthes cernua
Nodding lady's tresses
Sporobolus heterolepis****
Prairie dropseed
Stipa spartea
Needle grass
Thalictrum dasycarpum
Purple meadow-rue
Tradescantia ohiensis
Common spiderwort
Verbena stricta
Hoary vervain
Veronicastrum virginianum
Culver's root
Viola pedata
Bird's foot violet
Viola pedatifida
Prairie violet
Zigadenus elegans
White camas
The marked species are the 10 most widespread species for dry lime prairies (Curtis and Greene, 1949)
D: dry; DM: dry-mesic; M: mesic; WM: wet mesic

Brock, Thomas D. 2014. Legacy effects in prairie restoration: a 73-year spatial history. Proceedings of the North American Prairie Conference 23: 15-20.

Umbanhowar, C.E. Jr. (1992). Reanalysis of the Wisconsin prairie continuum. American Midland Naturalist 127: 268-275.

Curtis, J.T. and Greene, H.C. 1949. A study of relic Wisconsin prairies by the species-presence method. Ecology 30: 83-92.

Curtis, J.T. 1959. The Vegetation of Wisconsin. University of Wisconsin Press, Madison, Wisconsin.

Henderson, Richard. A. `998. Plant species composition of Wisconsin prairies. Technical Bulletin No. 188, Wisconsin Department of Natural Resources, Madiosn, Wisconsin.

Cochrane, T.S. and Iltis, H.H. 2000. Atlas of Wisconsin Prairie and Savanna Flora Technical Bulletin No. 191, Wisconsin Department of Natural Resources, Madison.