Azaleas

Answer 1

To properly fertilize your Azalea you should have your soil tested.

Without a soil test, use a balanced fertilizer.
Remember that Azalea have a shallow root system and can easily be damaged by fertilizer.
Most times your soil with a dressing of organic material or mulch is often all that your plant needs.
If and when you fertilize, I recommend once before blooming and once following blooming and use half strength.

https://www.gardeningknowhow.com/ornamental/shrubs/azalea/fertilizer-for-azaleas.htm