Rhododendrons love the relationship of being dry, then wet, hence watering every day for a brief period of time is ideal during growing months(May-July). This mimicks the natural ecological system whereby rhododendros thrive.
Here is what you should NOT do:
Don't plant them in low areas that are always saturated.
Don't plant them in full sun without irrigation.
Don't plant them below grade.
Don't allow them to have dry roots in the morning of a scorching hot day.
Don't over water them in the Fall.
Don't let them go into a freeze with dry roots but rather wet roots.
Don't water them at dusk for foliage diseases will set in over night.
Try not to water them on humid cloudy days, let them look for moisture.
Think of trying to grow roots as well as foliage. To do this, force the roots to "GO GET" moisture. This way, roots will travel in search of moisture. Give them moisture, then dry them out again. This occilating process builds healthy root systems which will insure the plants survival in hard droughts and bitter winters.
