The purple spikes of wild lupine (Lupinus perennis) and yellow splashes of hoary puccoon (Lithospermum canescens) are fading in the oak barren remnants along the Paint Creek Trail. Both species flower in May and early June each year, and are toward the end of their flowering periods this year. These plants give us small reminders of the special plants that used to be more widespread in the oak barrens of southern Michigan, but have mostly disappeared. As these plants have disappeared, many of the pollinators (think bees, moths, butterflies, and wasps) that rely on these native plants have declined or disappeared too.
Oak barrens, which used to cover about 2% of Michigan and 28% of Oakland County, are a type of savanna that typically has low tree cover. The ground cover in oak barrens contains prairie species in open areas and forest species in the shaded areas under widely spaced black and white oaks. Oak barrens are fire-dependent, which means that they need fire to keep them from becoming closed forest. Plants like wild lupine and hoary puccoon depend on fire to maintain their open habitat. Before European settlement, lightning strikes and fire intentionally set by Native Americans maintained oak barrens in this open state. As European settlers moved in, the open oak barrens changed quickly. Farmers plowed many savannas in the Midwest because they had few trees. Settlers also extinguished the frequent, low-intensity fires that the oak barrens needed to survive. Within a few years, trees quickly grew, the canopy closed, and the open oak barrens became forests.
As we work to restore oak barrens in Oakland Township, we collect seeds from the native plants in our prairie and oak savanna, including wild lupine and hoary puccoon. We hope that by restoring oak barrens, both native plants and animals will benefit. If you’d like to help collect seeds, or learn more about prairie and oak barrens restoration, please check out our volunteer opportunities!