ARBORETUM NEWS (NATURALISTSNOTES)

Curtis Prairie and Noe Woods Walk

SUNDAY, MAY 27, 2012

Are we growing asparagus out on Curtis Prairie? It looked like that to some visitors today. However with a closer look, we could see that some of these plants had lost their asparagus looking spears as they bloomed – the part that looked like the spear of an asparagus had become a foot long or more stalk or raceme of bright, milky white flowers. The flowers are relatively small (about 1 inch) and tube shaped, typical of plants in the bean or pea family. This plant is called White Wild Indigo (Baptisia alba macrophylla).It has an important role in the prairie. It has the ability to support and feed a type of bacteria that will grow on its roots and take nitrogen from the atmosphere that can not be absorbed directly by the plant and “fix” into a form that can be used by the plant. Eventually, when the dried out plant parts of the wild indigo are incorporated into the soil, this usable form of nitrogen will be available to other plants rooted in the surrounding soil. Along the trail leading west parallel to Arboretum Drive we saw another familiar plant that is also in the bean family. It has small compound leaves, drooping tube like flowers, and lacy tendrils that gardeners will recognize as a relative of our garden pea and bean plants. This plant is called Hairy vetch (Vicia villosa). It has deep purple flowers, which have white or pinkish tips when they first bloom. You probably have seen vetch with small yellow or white flowers growing on farmland and along roadsides. Many of these non-native vetches were introduced as cover crops, forage plants, and also for their ability to add nitrogen to the soil.

We couldn’t help but notice large stands of two shrubs on Curtis Prairie. Both have been blooming for a few weeks. One easily recognizable one was large stands of rose bushes. Although we could clearly see that this thorny bush with a showy, papery thin pink petals was a rose, the authors of Prairie Plants of the University of Wisconsin-Madison Arboretum state that this rose, the Carolina or Pasture rose (Rosa Carolina) is “Wisconsin’s most variable native rose,” and will freely hybridize with the Prairie rose. The other shrub, also in large stands, has small pyramid shaped clusters of white flowers – Gray dogwood (Cornus racemosa). Both of these shrubs have seeds that are spread by animals, but they also will spread out and reproduce vegetatively, thus forming the contiguous dense stands we saw today. The roses reproduce from shallow rhizomes and the dogwood from suckers.

As we entered the dappled shade of the oaks leading to the western portion of Curtis Prairie we saw the last blooms of the colorful red and yellow flowers of Wild columbine (Aquilegia canadensis), the small white flowers at the end of the arching leaves of Solomon’s plume (Smilacina racemosa), and Tall beard-tongue (Penstamon digitalis). All the Wild geraniums (Geranium maculatum) had shed their five petals and had begun developing their seeds. When the seed walls dry up they will curl back and send the seeds catapulting out in all directions. Wild geraniums also grow by rhizomes, and often are seen in dense colonies. We did see the last few of the purplish pink flowers on a few geraniums in Noe Woods. Just outside of the woods along the path edges, Common milkweed (Aesclepias syriaca), a host plant for Monarch butterflies are about to bloom. From the paths in west Curtis Prairie and the adjacent Noe Woods we had many examples to compare of Downy phlox (Phlox pilosa) and Dame’s rocket (Hesperis matronalis). Although the plants look very similar in both color and shape, especially from a distance, Dame’s rocket can grow to about 36 inches and Phlox will be about 20 inches maximum. However, the most distinctive difference is that Dame’s rocket, being a mustard family plant, will have the characteristic of four separate flower petals, and it quickly form whorls of elongated upright seed capsules in the upper parts of the stem. Phlox has five petals, and seeds forming in rounded capsules forming where the flower petals dropped off.

Our group today included a Boy Scout troop leader. And, the boys missed out on a tour de force of variation amongst poison ivy (Toxicodendron radicans). Within a 30-minute walk through the west edge of Curtis Prairie and Noe Woods, we saw poison ivy leaves with red tints, pale green hues, and deep green hues. Poison ivy growing in low carpets amongst the ubiquitous Virginian creeper. Poison ivy looking a lot like the few box elder saplings we saw. Poison ivy in small inconspicuous vines and poison ivy in thick bold hairy vines extending 80 feet into the treetops. So, those of us with long pants and socks got tucked in, and the rest of us stayed in the center of the trail – and with this caution, a bit of shade and a few breezes we all came through this 90 plus degree day just fine. We also saw black raspberry at the end of its bloom on the edges of Noe Woods and a last gasp patch of Shooting stars (Dodecatheon meadia) as we re-entered west Curtis Prairie.

Paul Borowsky
Naturalist

Located between Lake Wingra and the West Beltline Highway at 1207 Seminole Highway, the University of Wisconsin-Madison Arboretum features the restored prairies, forests and wetlands of pre-settlement Wisconsin. This 1,260-acre arboretum also houses flowering trees, shrubs and a world-famous lilac collection. Educational tours for groups and the general public, science and nature-based classes for all ages and abilities, and a wide variety of volunteer opportunities for groups, families and individuals are available.