Flag created by CincyFlags for the neighborhood. 
Its symbolism, according to CincyFlags in [1]:
"Half of the tree illustration made to represent the carved green man face in Green Man Park.
Blue, Gold and Green colors taken from the Walnut Hills Community Council’s existing identity.

Lush green leaves complete the tree illustration to symbolize green outdoor spaces like Eden Park."
Own work using: https://www.cincyflags.com/walnut-hills-1
CincyFlags