Boron poisoning or fertilizer burn will create these symptoms.

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Fertilizer Burn photo by Harold Greer

Burn is generally at the ends and edges of leaves and will be on any area of the whole plant, not just on the sunny side. Give as much water as possible to wash fertilizer out of roots.

Here is a link that might be useful: Rhododendron Basics by Harold E. Greer

A few questions:
1. Have you applied any boron?
2. How much water -- rainfall or given by you -- does it get?

Anyway, I suspect that, instead of boron poisoning, the problem could be as simple as drought stress because the plant hasn't yet developed a good root system.

It probably isn't boron, but most likely is fertilizer poisoning.

Drought causes all leaves to wilt and new leaves to burn, and eventually all leaves begin to turn brown. Most of your new leaves look good and they would be the first ones to suffer from drought. I don't know about where you live in NJ but here in PA we have had quite a bit of moisture as we normally do.

lawnkid,

Let's get to the bottom of this.

Have you fertilized? If so, when, with what, and how much?

Ok

I did not applied boron, unless it is contained in Hollytone.

I think I have watered appropriately. I constantly monitor rainfall around my garden as I keep different plants with different water requirements.

In April 1, 07 I applied ½ cup of Hollytone around the base of the plant. I was very careful to spread the fertilizer evenly around the base of the plant. I think a covered a diameter of 12" to 18", paying attention to cover where the base of the plant was (this was a container plant, and thatÂs where the root extent at that point). This was early spring and I did not observed the plant to start doing any grow for the season until mid May. The first growth is usually observed on the buds. They start to swell as the flowers start opening the bloom.

I have 5 rhodys and 5 azaleas I planted last fall. After going through the long winter I was anxious to see them bloom and take in on new growth. In my mind I though this plant are fairly big and could benefit from more fertilizer than what I put on April 1st , so I decided to put in a little more. This time I have informed myself I found out that coffee grounds is an excellent organic fertilizer for acid loving plants. Also I wanted to do something to acidify the soil, so I purchase "Garden Sulfur" from Espoma.

In late May I made a second fertilizer application to each of the azaleas and rhodys. This time I used less Hollytone, about a cup of spent coffee grounds and teaspoon of sulfur(recommended amount). Again I made sure to spread this mix evenly around the base of the plants. I spread the Hollytone, then layered the coffee grounds on top, sprinkled the sulfur evenly then cover with 2" of mulch. After that I watered.

For this particular plant I noticed it bloom nicely two weeks after the second fertilization, but after that I noticed that some of the sides of the leaves were getting browner. (Please look at the links above to see the before and after photos). I think Rhodyman suggestion makes sense. The photos he posted on the follow up resembled closely the behavior I am seeing in my plant.

At this point my conclusion is fertilizer burn. I am thinking to go back, move the mulch away from the base, scrape the top layer out (by hand, I heard about the shallow roots) maybe ¼" so that this excess of nutrients do not continue to be absorbed by the plant. Give a good water, and replace the mulch.

lawnkid,

Thanks for coming back with more info.

Chalk this up to "live and learn." It happens to everyone, including gardeners!

Have fun in your garden.