Osmocote® Azalea, Camellia, Rhododendron Smart Release® Plant Food is a good fertilizer. I like Holytone or MagAmp better, but all three are good. Whatever you do, DON'T follow the directions on the Osmocote package.

Do not mix the fertilizer into the top 1 to 3 inches of soil. That is where the roots are since rhododendron and azaleas have shallow roots. Do not cultivate around rhododendrons and azaleas. Just mulch them. When fertilizing, pull the mulch back, sprinkle the fertilizer on top of the soil and then put the mulch back over the fertilizer.

Also, do not reapply every 4 months. Only fertilize in the spring and at half the rate on the package.

The primary reasons rhododendrons and azaleas decline is:

1) poor drainage. They need well drained soil.

2) soil not acidic. They need an acidic well-drained soil.

3) too much shade. They need an acidic well-drained soil in a location that get at least 2 hours of sun each day in order to set buds.

4) drought during summer. The need to be kept moist (not wet) while they are forming flower buds during the summer.

For many of us, this past winter our plants took a beating with the very unusual winters some of us had with warm weather followed by late freezes. They have what is more typical of drought damage but in this case was caused by the warm weather followed by late freezes. It causes Botryosphaeria dothidea which causes leaves to turn dull green and then brown and roll and droop. Cankers form on branches which may girdle the branch.

This is the most common disease of rhododendrons in the landscape. A typical symptom of this fungal disease is scattered dying branches on an otherwise healthy plant. Leaves on infected stems turn brown, then droop and roll inward. These leaves often lay flat against the stem and will remain attached. The pathogen can infect all ages of stem tissue through wounds, pruning cuts, and leaf scars. Heat, drought stress, and winter injury can increase disease incidence. Cankers on branches can gradually grow through the wood until the stem becomes girdled. Diseased wood is reddish brown in appearance. Discolored wood viewed in longitudinal cross section often forms a wedge that points toward the center of the stem, and the pith may be darker brown than the surrounding wood.

Sanitation and applying a fungicide such as metalaxyl (Subdue) after pruning my provide some control. Plants should be grown in partial shade, with mulch and kept well watered during dry periods. All dying branches should be promptly pruned out in dry weather and all discolored wood should be removed. Plants should also be protected from rough treatment during maintenance activities to prevent unnecessary wounds.

Here is a link that might be useful: How to grow rhododendrons and azaleas.

Kris, I'm seeing one part of your question Rhodyman missed - "I never prune or deadhead (What is DH anyway?)"

Deadheading is snapping off (just use your fingers) the spent flowers after your rhododendron is done blooming - good sanitation and also prevents your plant from spending unnecessary energy in setting seed if you have no plans to harvest rhododendron seed. And if you meant DH in general as you often see in these forums....Dear Husband. Sometimes Dam-ed Husband depending on the context of the message :)

Thanks guys, I sprayed Mancozeb (manzate) on my roses for as a fungicide. I sprayed it on the Rhodies too. Will it work for Rhodies too? I heard its powerful?