Good drainage is essential for azaleas. Organic matter added to the soil improves drainage in clay soils and will increase a sandy soil’s ability to retain water and nutrients. Current research has determined, however, that organic amendments should not be added just to the planting hole, but to as large a planting area as possible. In heavy clay soils, these amendments may actually hold excess moisture in the root zone when added to a small planting hole, creating a “bathtub” effect.

Azaleas do not tolerate wet soils, so it is important to avoid this problem by digging and amending a large area when planting them. The area of the bed should be large enough to accommodate the plants at maturity and space for the plants on the outside to spread their roots. Information on mature plant size may be on the tag attached to the plant at purchase, but you may have to inquire with the salesperson or look this information up in a book.

When planting two or more types of plants together, add their ultimate (mature) spreads together and divide by the number of plants to calculate their spacing. For example, if planting an azalea with a mature spread of 4 feet with another type of shrub whose mature spread is 6 feet, the planting distance between them is 5 feet (4 + 6 divided by 2). Some “common sense” adjustments may have to be made at times when expected growth rate and plant spread may be reduced because of less than ideal conditions, or if vigorous and slow-growing plants are planted together.

After calculating the area of the bed, dig the entire bed 6 to 8 inches deep. If you choose to add organic matter to improve drainage, mix in 4 inches of composted pine bark throughout the bed prior to planting.

Place each plant in the bed based on the space needed for growth to its mature size. For each plant, dig a hole only as deep as the root ball. The top of the root ball should be level with (or just slightly higher than) the ground level. It should not be lower than ground level.

Tamp down the area on which the root ball will rest to give it some firm footing. This will also prevent it from sinking below the level of the soil. After planting, lightly pack the soil around the roots. Water plants to eliminate air pockets. Do not fertilize azaleas at planting; newly planted shrubs can be fertilized after they become established.

For single plants, dig a hole the same depth as the root ball and two to three times wider than the area to be covered by the branches of the plant you are setting. Place the plant in the center of the planting hole (be sure the top of the root ball is level with or higher than the ground level). Shape a ring of soil about 3 inches high and 2 feet from the main stem to direct the flow of rainwater to the plant.

If the chosen planting site is not well-drained, prepare a raised bed. Elevate the area to ensure good surface and internal drainage. Dig a shallow hole (or bed) so that the top of the root ball is not at ground level but elevated several inches above ground level. Build up around the root ball with topsoil.

Most soils in South Carolina are acidic enough for optimum growth of azaleas except possibly around the foundations of new homes. Discarded mortar in these areas often causes the pH to become too basic for azaleas. This soil should be removed and replaced with new soil before planting azaleas. Have soil tested to determine pH and fertilizer requirements.