The rare yellowwood tree is an outstanding feature of this preserve. Ogle Hollow is one of the few places in Indiana where these trees are found. In addition to the yellowwood, chestnut oak and black oaks are found on the upper slope. Red and white oaks are at lower elevations. The understory has beautiful flowering dogwood and redbud, mixed with pawpaw, spicebush, ironwood, and blue beech.
Wildflowers also add their color during the growing season.
Christmas fern is widely distributed, and often associated with maidenhair fern and narrowleaf spleenwort on the slopes.