Gardening in Gwinnett: No need for concern for azaleas with yellow leaves

Recently, the extension office has had several calls from homeowners concerned the leaves on their azaleas are turning yellow. Often the older leaves turn yellow while the younger leaves remain green; however, sometimes many of leaves are turning yellow and orange. Normally, the older leaves turn yellow and die and are replaced by younger, green leaves. If most of the leaves are yellow, then a problem exists.

The yellowing leaves may also have been brought on by the drought. Azaleas are temperamental plants with a shallow, fibrous root system. They like well drained but moist soils. Also, azaleas planted in areas not suited for them, such as those with full sun, will also develop yellow leaves.

Often the cause is lack of fertilizer. The azaleas did not receive adequate fertilization, especially nitrogen, during the growing season, or did not efficiently absorb the fertilizer applied due to stress.

The yellow leaves are no cause for worry. In most cases they will bloom in the spring as they normally do. Do not fertilize them this time of the year because fertilizer may cause the plants to break out of dormancy and start growing. The new growth is susceptible to frost and may be burned back by our winter weather. Wait until after the danger of frost is past, roughly April 15 for our area. Plan on fertilizing them early spring when they begin to leaf out. Use a general purpose fertilizer such as a 16-4-8 or 15-0-15.

If the azaleas receive the proper amount of sunlight, water, and nutrient, they are less likely to develop problems and are also less susceptible to pests. The yellow leaves may not look good, but in all likelihood, the plants are alright and will prosper in the spring and summer if given adequate water and fertilization.

Timothy Daly, MS, is and agricultural and natural resource extension agent with Gwinnett County Extension. He can be contacted at 678-377-4010 or timothy.daly@gwinnettcounty.com.