The Rapp Family Ravine Garden is a historical garden and a major feature of the Oldfields estate. The Ravine Garden was designed in the 1920s by Percival Gallagher. Located behind Lilly House, the estate's mansion, the one-acre Ravine Garden descends more than 40 feet to the edge of the Indianapolis Water Company Central Canal.
Restored in 1998 with generous funding from George and Peggy Rapp, their family, and other generous donors, the Ravine Garden features a cascading stream, three rock-rimmed pools and more than 19,000 bulbs, perennials, trees and shrubs. Many of the plant varieties featured are the same as those specified in Gallagher's original plan.
- Bush Clover (Lespedeza thunbergii), a shrub with pea-shaped flowers that bloom in late summer and fall
- Kwanzan Cherry (Prunus serrulata), a double pink spring blooming tree that reaches 30 feet
- Showy Lady Slipper Orchid (Cypripedium reginae), an endangered native orchid that is hardy in Indiana
- Irises, including many of the exact varieties planted in the original Ravine Garden plan, which were found with assistance from the Historic Iris Preservation Society
- Statuary, including Nymph and Fawn, a bronze sculpture by Isadore Konti from the IMA's collection of fine art