In this paper we study the benefits of applying Software Defined Networking (SDN) to control forwarding in a network of constrained wireless edge devices. The proposed architecture is applicable to dense Small Cell deployments featuring wireless backhauling and edge computing capabilities, or to wirelessly connected sensor nodes following the fog computing paradigm. The paper introduces a novel path forwarding policy based on SDN, and presents an experimental evaluation demonstrating the benefits of the proposed policy to mitigate external interference, achieve flow balancing, and cope with CPU constrained devices.