The combination of shade and drought presents a challenge, few plants are able to tolerate the situation of lack of light and moisture. The first line of attack is to improve the soil with lots of organic matter. Plant selected species closer than is usually recommended, mulch after planting, or establish an under planting carpet of drought resistant ground cover plants like Pachysandra or Tellima. Such actions helps to retain moisture and reduce surface evaporation. Shrubby plants will grow more slowly than usual and generally plantings will take longer to establish, the reduced vigour will mean there should be less of a need to prune.