Plant rhododendron in early spring or fall. Dig the hole twice as wide as the root ball or pot. Dig the hole as deep as the root ball is tall. The top of the root ball should be about 2 inches above the level of the surrounding soil, so return some of the soil to the bottom of the hole to lift the shrub. Set the root ball in the hole and return the removed soil around the root ball. Water to settle the soil.
Spread 2 to 4 inches of mulch (wood chips for example) around the shrub. Keep the mulch about 2 inches from the stem of the shrub. Mulch helps to retain moisture and helps to block weed growth.
Water weekly for the first month after planting if there is no rain (sandy soil may require more frequent watering). If planting in the spring, continue to water twice a month into fall. After the first year, rainfall should provide enough water. Fertilize, if desired, using a commercial fertilizer specifically designed for use on rhododendron. Apply according to the manufacturer's instructions. There is no need to prune rhododendron except if a branch is dead or damaged.