Answer: Soil pH is a common ailment of azaleas as is poor quality water and lack of water. You mentioned the leaves were turning yellow. If it is the young leaves (those near the end of the shoots) turning yellow, I would suspect an iron deficiency. Treat with a chelated iron product.
If older leaves are yellowing, the cause may be the transition from winter to spring. Many of our evergreens in the south go through this transition as their older leaves yellow and begin to drop. There is no need to be concerned with this.
If the entire plant is yellowing, you may have a nagging root problem caused by seasonally drought or excessively wet soils, compacted soil and low organic matter content, and possibly root rots.
Often water quality can be a factor. High pH, high sodium, high salt content, and high chlorine can all stress plants resulting in symptoms such as you described.
Have your soil tested and if pH is a problem, begin making adjustments using powdered sulfur at the rate recommended on the test report. Continue feeding plants with an acidic fertilizer. Avoid manure as it is usually high in pH and often high in salt content. An acidic, organic alternative is cottonseed meal. Keep plants well mulched and water enough to avoid drought conditions.
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