We consider the problem of multicasting multiple description (MD) video in wireless ad hoc networks. We follow an application-centric, cross-layer approach with the objective of minimizing video distortion. The contribution of this paper is twofold. First, we propose a practical MD video multicast scheme that uses multiple trees to achieve an improved error resilience performance. The proposed scheme also takes into account highly diverse wireless link bandwidths by using scalable coding for each description, thus further improving the overall video quality. Second, we formulate the optimized multicast routing as a combinatorial optimization problem and propose an efficient Genetic Algorithm (GA)-based metaheuristic solution procedure. Performance comparison with existing approaches show significant gains for a wide range of network operating conditions.