Question
I have varying kinds of azaleas in my yard.....all planted in good draining sandy loam soil in the Central Valley of California. All have been doing well except that some have developed severe chlorosis and the leaves have turned yellow. I have added an iron supplement but it dies not do the job....I also have some Rhododendrons that do not exhibit any chlorosis...what can I add to help get the azaleas healthy again? thx......Ray Kent  

Answer
Ken, Well, this one is a bit tough, I live in Minnesota, and we do not have near the ability to grow the varieties of Azaleas that you do there, but most types of them are the same from ones that grow here, and there in CA. Here is what I would look for and do in any case, How long have they been there? are they new, or older, and if so, have they ever had this problem before? The first thing I would do, if you have not done so already is get a good soil test kit, that tests for iron, and make sure that iron chlorosis is the problem. Check the PH of the soil. Azaleas like an acidic soil, so you will want to check that as well. are the plants in question at a lower grade than others? is it possible that, even in sandy soil, they are getting to much water, and in effect drowning? I am guessing not, being in sandy soil, but its worth checking, if you have gotten a lot of rain, or they get a lot of water from another location, get a thin long wood stick or dowel, and push it down into the soil 10-12 inches, and 6-8 from the base of the plant, if it comes out really dark and wet, they may be getting to much water. If you cannot find a good soild test kit, you may wnat to contact a University in your area, if they have an agriculture department, they may do soil testing, and it is often less expensive, more extensive, and accurate than what you could get in a store. they may also have other ideas for Azaleas. I hope this helps a little bit, this is a tough one, you may also want to check with a local garden center, and see if they have a horticulturalist on staff, they could help you out a lot, as you may need to bring in a sample of the leaves, it could be something more comman to your area than here in MN. Good luck with the Azeleas, and happy gardening.

Mark