ARBORETUM NEWS (NATURALISTSNOTES)

CURTIS PRAIRIE

SUNDAY, SEPTEMBER 22, 2013

Sunday’s tour focused on the John T. Curtis Prairie. September 20th marked the 100th anniversary of Curtis’s birth, and we chose to spend the weekend honoring his work and his legacy. One of the best ways to do that is to take a stroll in the prairie bearing his name.

I cannot tell a lie – the prairie is beautiful in all seasons. But it is especially gorgeous right now, with red and coppery shades predominating, and cobalt-blue bottle gentians peeking out from under the taller plants.

2013 is a good year for big bluestem.

Big Bluestem and Indian grass

Last year the species did not reach its full height due to drought conditions. The plants were healthy – they just weren’t as tall as usual.

Not so this year. Big blue towers overhead, and Indian grass comes in a close second. The latter’s feathery heads are a marvelous, rich shade of bronze.

Clusters of orangey-red rose hips are very visible along the prairie firelanes. At first they could be mistaken for berries.

wild rose hips

The hips swell and develop after the flower’s lovely pink petals fall off; inside, seeds are maturing. Rich in Vitamin C (ascorbic acid), rose hips impart the red color and tangy flavor to “Red Zinger” tea. Those hips which are not eaten by wildlife will persist on the plant until early next summer, but by then they’ll be brown and shriveled. In September they are round, firm, and bright red, like tiny apples.

You can easily see at least four species of goldenrod right now: Canada, showy, stiff, and grass-leaved. If you are lucky and

common buckeye on grass leaf goldenrod

observant, you might spot Riddell’s, looking almost like a miniature cornstalk with its center-creased leaves, or old-field, with its “layered look” to the inflorescence.

One more time, now: goldenrod does NOT cause hay fever allergies. Ragweed is the most common culprit there.

At least four species of aster are also readily identifiable. New England is the

New England aster

easiest – it’s the tall purple one, with the leaves which partially wrap around the stem, leaving two small “ears” on the opposite side. The flower color can vary from violet to pink.

Of the white asters, which I warn you can get confusing, calico is the one with the very small flowers and open, branching shape. Of somewhat similar growth habit but noticeably larger flowers is frost aster – so named because it takes a really hard killing-frost to knock it out for the season.

Heath aster has small flowers in a dense, often pyramidal head. It also has teeny-tiny leaves, reduced almost to needles, and it’s shorter in stature. You can see it in the remnant prairie.

No less an authority than Ted Cochrane, curator for many years of the UW-Madison Herbarium, said this about identifying asters: “ … the process is challenging, and much judgment is needed … ” He also states that many asters spontaneously hybridize, further muddying the identifying characteristics. For all of those reasons, I am going to stop at four species for right now.

Tan fuzzy heads of Joe-Pye-weed currently dominate the Arboretum’s savanna landscapes. Look at the whorled leaves of this tall plant to find evidence of leaf miners – tiny insect larvae which move around in between the layers of the leaf, eating chloroplasts as they go and leaving pale trails or blotches behind. White snakeroot, presently lighting up woodland edges throughout our area, is another very good host to leaf miners.

In prairie and savanna, gray dogwood is

bluebird in gray dogwood

busily producing white berries on red stems. These fruits have been found to have a 39% fat content – the highest percentage of any other Wisconsin berry. (Bayberry is slightly higher, but it’s not native here.) Accordingly, gray dogwood berries are very popular with – and necessary to – migrating birds, who need to build up their fat stores before undertaking the grueling ordeal of migration. The birds will strip gray dogwood shrubs absolutely bare, leaving only the pinkish, branched stems as evidence that the plant ever bore fruit.

Along the interior diagonal trail in the Curtis Prairie, a few late coneflowers can be found, pleasant pink surprises amongst the burnished grasses and yellowing leaves. And goldfinches are still flitting about between the dried stalks of sawtooth sunflower, sometimes giving their potato chip-potato chip calls. Soon the male goldfinches will molt away their yellow feathers and assume the “olive drab” color they wear all winter.

Goldfinches nest very late in the summer, using thistledown to line their nests.

goldfinch nestlings

If they needed to migrate, they probably could not pull off so late a breeding season; but they stay here all winter, so the young have time to quickly mature before cold weather sets in.

Throughout Sunday’s tour we spotted vivid blue bottle gentians hiding beneath taller vegetation. Once you learn to look for that color, you find more and more of it. A visitor asked a gentian question I could not immediately answer: how do the seeds have time to mature, given that the plant flowers so late in the season? What’s their timetable? The guidebook in my pocket did not give the answer.

I have not found a definitive answer yet, but I strongly suspect that they simply develop very quickly (sort of like young goldfinches) and are ripe before winter arrives. I have learned that the seeds are very small; and if one chooses to plant gentians from seed, the advice is to do it in autumn or early spring. Mother Nature probably does the same thing, implying that the seeds are ready to “leave home” before the snow flies.

We had two notable bird encounters before our trek was over. A lone sandhill crane circled above us while we traversed the prairie; and as we wrapped up our tour at the steps of the Visitor Center, a red-tailed hawk swooped over the parking lot and lighted on a lamppost, flaring its orange-red tail feathers as it landed.

Orange, copper, cobalt: the colors of our day. Go out and find them!

Kathy Miner, UW Arboretum 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.