Yes, your azalea probably needs repotting in fresh potting mix. Over such a long time the mixture can become compacted and lacking in organic matter. In addition, azaleas need a pot large enough to their provide roots with sufficient room and drainage.

Fill the new pot half-full with potting soil. Azaleas prefer loose, well-drained soil. If using straight potting mixture, it may be necessary to mix in some organic mulch to create a looser mix. Up to 50 percent of the potting mixture can be mulch. The best mulch is naturally decomposing wood and leaf mold from oak or pine wood. Other good materials are leaves, pine needles, and sawdust. Alternatively, you may want to use a potting mix for acid-loving plants or mix sphagnum peat moss into standard potting soil.

When repotting, take care not to harm your azalea's shallow roots. Remove the plant from its current pot by tilting the pot upside down and gently shaking the plant out of the pot. Do not pull the azalea from the pot--that could damage the roots. It's okay if dirt falls away from the roots, but don't shake the dirt off as a large clump of falling dirt could damage the roots.

Place the azalea roots on top of the soil and mulch mixture in the new pot. Steady the plant with one hand and scoop dirt in around the plant with the other. Don’t pack the dirt around the plant; simply fill in the gaps, as azaleas do best with loose soil.

Fill the pot the rest of the way to the rim with mulch. Leave an inch of space around the stem of the azalea without any mulch. Water the repotted azalea slowly and evenly, and water every day for a week. The water helps settle the soil and provides the disturbed roots with easy access to water until they have had a chance to spread into the new soil.

Prune in early spring before new growth appears, and prune as the azalea blooms to encourage more flowers (The cut flowers look beautiful in a vase).

 The Azalea Society of America provides extensive information on azalea care.

For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service