Oxbow Prairie, formed by an old loop in the river’s course, lies northwest of Bunker Hill.
This old oxbow in the Chicago River’s North Branch is a combination of low, wet prairie soils and slightly higher mesic prairie soils. A small open savanna lies on what was once the east bank of the river. The mesic prairie area had been mowed by the FPDCC for recreational use and had an abundance of Eurasion grasses, Queen Anne’s lace and tall goldenrod. With management, the more conservative prairie plants such as northern dropseed, stiff goldenrod, golden alexanders and big bluestem grass are returning.
The wetter areas are richest in native plants, including cup plant, ironweed, tall meadow-rue, water parsnip, cord grass, Virginia rye, and numerous kinds of sedges.
A small oak savanna on the old east bank has swamp white and bur oaks, in the words of landscape architect and restorationist Tom Vanderpoel, “a wonderful micro oak savanna.”
Between the prairie and the river lies a large floodplain woodland of cottonwood, basswood and box elder, where invasive garlic mustard dominates the understory. No restoration work has been done in this area yet, and poses a challenge for the future.