My house was pressure washed and painted last fall. Since then, my two rhododendrons closest to the house that had been thriving have turned very sickly. They're not completely dead, but most of their leaves have turned brown and curled and are falling off. New green leaves cover about 15% of one, and 30% of the other.

I believe that a bleach-based solution was used for the pressure washing, and I am wondering if this runoff might have increased the pH of the soil near the house enough to damage the plants.

I'm planning to test the soil's pH, then try to correct any acidity issue. Am I on the right track? Any suggestions for correcting the pH? Thanks.