Azaleas are perennial, acid-loving, flowering shrubs. These shrubs prefer very well-drained soils and typically require little fertilizer, as long as the soil is not too alkaline. Your young azalea will do best when you attend well to its soil, watering and pruning needs--the latter is especially important if you want your azalea to grow bushy rather than leggy. Azaleas young or old are not particularly difficult to care for and can enhance your garden for many years.
Place organic mulch around young azaleas after planting, leaving a little space between the mulch and the stem to avoid stem diseases. Pine wood chips, peat moss and organic compost are suitable mulch material for these plants. Mulch keeps the young azaleas moister and, according to azaleas.org, as the mulch decomposes it will add necessary nutrients to the soil .
Encourage a fuller look in young azaleas by pinching the tips (the new growth) off as they grow. However, as explained by rhododendron.org, you should not pinch the tips too soon while they are still soft or you'll defeat the purpose of pinching (to promote bushier growth), Wait until tips snap easily.
Watch the young azaleas for signs of nutrient deficiencies. These signs include yellowing leaves and lack of new plant growth. Azaleas.org recommends soil testing, however, before applying fertilizer for azaleas--the soil amendments necessary will depend on the soil's particular deficiencies. Note that fertilizing young azaleas unnecessarily may cause them to grow quickly, but not flower--all the energy may be spent towards green foliage growth and your young azalea may grow big, but not so beautiful.
Water your young azaleas daily--enough to keep them moist but not so much as to promote fungal diseases. If azaleas are planted on high ground or in a raised bed, where water does not pool, and the soil has good drainage (is not clay), this shouldn't be a problem. If your azaleas are standing in water puddles, however, they can easily develop diseases and die.