Ohio Rev. Code § 5529.11: Planting trees and shrubs may be permitted.

The director of transportation may, by a permit in writing, authorize the owners of property adjoining inter-county and state highways, at their own expense, to locate and plant trees and shrubs along such highways, subject to his approval as to kind, size, and location. The county engineer shall have the same authority on county roads and the board of township trustees on township roads.