A View from the Valley Grove Prairie
By Gary Wagenbach
(Note: The following piece was written prior to the tornado that swept the grounds on September 20, 2018. The grand old oak was taken in that storm and no longer stands. Please enjoy the photos and text below as an earlier piece of our story.)
On the left is the view I had when out on the Valley Grove oak savanna on a nice day in July cutting some of the invasive plants such as sweet clover. The bonus for the day was seeing threatened monarch butterflies and wild bees finding seasonal Valley Grove prairie flowers to their liking. You will be happy to know we have abundant patches of common milkweed, a key food plant for the monarchs.
White wild indigo (baptisia alba), shown in the middle image, is a dramatic addition to the midsummer prairie flowers. There are many more kinds blooming during July and August. Come out and walk the trails and see for yourself.
Often asked questions about the big bur oak on the southwest corner of the cemetery grounds include: How old? When does it produce acorns? How does it produce acorns? Are the young oaks just to the south offspring from the tree?
My answers: Age approximated is likely in the range of 200-250 years. Acorn production occurs some years, not every year, when the female flowers are fertilized by pollen from male flowers, i.e., both male and female on one tree (“one house” or “monecious” if you like the Latin/Greek label). Pollen from adjacent trees is the usual source of pollination. Self-pollination is said not to occur because pollen and female flowers mature at different times. We do think the nearby young oaks are offspring of the big tree.
About the Author
Gary Wagenbach taught biology and environmental studies at Carleton College for 39 years. He is a leader in off-campus studies directing ecology-oriented programs in Bermuda, California, New Zealand, Australia, and Tanzania. He also taught in Carleton’s Environmental Studies Program. His research interests include water quality issues and threatened species of freshwater mussels. He and his wife Linda restore prairie and forest on conservation land near their home and assist in managing the Valley Grove oak savanna restoration.
Gary is the President of the Valley Grove Preservation Society Board.