Growing Azaleas and Rhododendrons
Azaleas and Rhododendrons can be planted from early spring until fall. They will grow and bloom profusely if the following guidelines are used:
Location: Selecting a good site is very important. Filtered sunlight and protection from drying south and west winds is ideal. Make sure the location rapidly drains water. Azaleas do not grow well in dense shade or full sun. Do not plant under trees that are shallow rooted.
Soil Preparation: Azaleas require a soil that is acidic, high in organic matter, and drains well, but does not dry out completely. Soil in the Kansas City area is generally neutral with high clay content and poor drainage, therefore, soil amendments are usually needed, like Nature’s Blend Compost. Although Azaleas will grow in pure peat moss, a soil mixture with equal parts Sphagnum Peat, Garden Magic Top Soil, and Sand is recommended. Any heavy clay from planting hole should not be used. To acidify the soil, add approximately ½ cup Hi-Yield Iron Sulfate to the soil mixture and work in thoroughly.
Planting: The planting hole should be dug about 2 feet wider and 1 foot deeper than the root ball. Clay in the bottom of the hole should be broken-up as much as possible. While digging, save only the top soil for soil mixture. Set the plant with enough soil mixture underneath so that the top of the root ball is 2-3 inches above ground level. Finish backfilling with soil mixture, enough to cover the root ball, firm soil and soak well. Azaleas and Rhododendrons are shallow rooted and need a heavy mulch to conserve moisture and prevent winter injury. Use a 2 inch layer of Sphagnum Peat, Wood Mulch, Pine Needles, or Aged Leaf Mold. New mulch should be applied each spring.
Water: Newly planted Azaleas should have the equivalent of 1 inch of water every 7-10 days. Overwatering may kill the plant in sites where drainage is poor. If soil is moist but the plant still wilts, mist the plants lightly to increase humidity. Avoid excessive watering in fall. Plants will tend to harden off for winter if kept on the dry side. If fall is excessively dry, watering should be done after the first killing frost, usually around Thanksgiving. Use of an anti-transpirant, Wilt-Pruf, before winter will help keep the foliage from winter wind burn and drying out.
Fertilizing: Azaleas may need a light fertilizing soon after planting. Use only fertilizers recommended for acid loving plants, like Fertilome Azalea, Camellia, & Rhododendron Food. Established plants should be fertilized after blooming in the spring, but no later than July.
Pruning: Remove flower stems on Rhododendrons as soon as flowering is over, this practice is not necessary on most Azaleas. Break out only the dead flower cluster, not the young buds clustered at its base. To control the plant’s size or improve its shape, pinch out the soft, new shoots of vigorous growing plants. Do not pinch after July to allow time for flower buds to develop for next year. Dead wood may be removed any time it is noticed. Do not cultivate around Azaleas as they are shallow rooted!