“The oak savanna was once one of the most common vegetation types in the Midwest but is today highly endangered. Intact oak savannas are now one of the rarest plant communities on earth.” Savanna Oak Foundation, Inc.
One of several gardens that adorn Henry High School, the oak savanna is on the Newton Avenue side of the school. This unique garden was envisioned, prepared and promoted with a lively sign by then VISTA worker Sinda Nichols and a group of students in 2007.
Since then the primary custodian of our rare ecological space is community neighbor and volunteer Eric Nystrom. He has been assisted by Boston Scientific partners, Henry staff member David Silvestre, volunteer Susan Breedlove, and students of Henry Honor Society and the Herobotics Team.
What is an Oak Savanna?
Although definitions vary, one common definition is: “An oak savanna is a plant community with scattered “open-grown” fire-tolerant oak trees (there are currently two small burr oak trees). Other terms for these savannas are “oak openings” and “barrens.” In contrast to a forest, which has a closed canopy, the oak savanna canopy ranges from about 10 to 50 percent. In such a habitat, the ground layer receives sun and shade, which permits growth of a wide diversity of grasses and flowering plants. There is usually enough sun to the ground to permit the growth of typical prairie species, such as big and little bluestem grass, and many goldenrods and asters. An oak savanna is a transitional between tall grass prairie in the west and deciduous forest in the east. Oak savannas are now considered one of the most threatened plant communities in the Midwest and among the most threatened in the world. Less than 0.01 percent of the original savanna community remains.” NRCS Missouri 1 October 2003
Nystrom explained his involvement with the project: “Before I got there the garden had become a weed mess, non-natives had begun to take over. I want to show off native plants—that means that even the occasional pretty flower must go to maintain the biological integrity of the project. The small, confined space we’ve dedicated to this project lends itself to efficient monitoring of invasive bugs and weeds. I only wish we had a larger lot that could benefit more birds and insects that are necessary for developing a rich and healthy ecosystem. My other long term goal is that people who visit our oak savanna will observe how easy it is to maintain, once you get such a garden going and growing—hopefully in their own yards.”
Plants introduced in August 2012: Burr oak Quercus macrocarpa, Fragrant Hyssop (Agastache foeniculumn), Prairie Onion (Allium stellatum), Butterfly Flower (Milkweed) (Asclepias tuberosa), Smooth Aster (Aster laevis), Sky Blue (Azure) Aster (Aster oolentangiensis), White Prairie Clover (Dalea candidum), Purple Prairie Clover (Dalea purpureum), Pale Purple Coneflower (Echinacea pallida), Prairie Smoke (Geum triflorum), Ox-Eye (Heliopsis helianthoides), Rough Blazingstar (Liatris aspera), Wild Lupine (Lupinus perennis), Wild Bergamot (Monarda fistulosa), Showy Penstemon (Penstemon grandiflorus) and Prairie Spiderwort (Tradescantia bracteata).
Original plants that continue to grow in the Oak Savanna Garden: New England Aster, Goldenrod and Sumac.
Written by Susan Breedlove and Tom Murray