Tips for planting rhododendrons include selecting a site that provides partial shade, amending the soil so that it is slightly acidic and providing a mulch to protect the shallow roots. The plants should have deep green leaves that are neither yellowed nor wilted.
Rhododendrons do well in the United States Department of Agriculture hardiness zones 4 through 9, areas where summers are wet and winters are not too cold. However, they require some cold weather to ensure strong flowering.
Prepare the planting bed by adding oak leaves and compost or peat moss for well-drained soil that is at the ideal pH of 4.5 to 6 for growing the plants. Avoid planting the roots too deep in the soil so they do not rot. After establishing the plants, mulch them annually using pine needles or pine bark chips to a depth of 2 to 5 inches. The mulch protects the shallow roots while retaining moisture.
In areas that receive less than 1 inch of rain per week, rhododendrons require irrigation. If the roots dry before the gardener waters again, they produce fewer flowers. The plants do best with a light application of fertilizer during the spring. Over-fertilizing causes them to burn.