Azaleas prefer a soil of high organic content, markedly on the acid side, ideally with a pH range of 4.5 to 6. If necessary, soil sulfur or aluminum sulfate should be added to acidify neutral or alkaline soils. Ample quantities of leaf mold, well-decomposed compost or peat moss, which will help make it acidic, should be incorporated into the soil prior to planting. Set plants out in a shaded or partially shaded location (the more shade the further south you are), in a location protected against drying winds. Soil should be moisture-retentive but well-drained.
Spacing is determined by the ultimate size of the plants chosen and by the rapidity with which you wish to achieve landscape effect – in general 3 to 5 feet apart is proper. Of paramount importance is the depth to which Azaleas should be planted – never set the plants with the top of the root ball any deeper than the surrounding soil level!
Because they are shallow rooted, Azaleas should not be cultivated. Instead, use a mulch of for example pine needles or leaf mold. This will hold moisture and discourage weeds. In poor soils, or to enhance slow-decaying mulch, add a special azalea fertilizer in spring before new growth appears. Water deeply once a week when there is little or no rainfall. Prune after flowering only as necessary to remove dead or unwanted branches; pinching the tips of new shoots will encourage bushiness.