Rhododendron advice from the Seattle Times: First recite the gardener's mantra, "Right plant, right place." For rhodies that means well-drained soil loaded with organic matter. For a new planting, spade and add compost to the entire area, not just the hole. Plant no deeper than it was in the nursery container. Rhodies like the acid soils of the maritime Northwest and an acid-based fertilizer before bloom. Most want dappled shade, and they may go thirsty if planted next to greedy tree roots.