sulfer and no more lime

Have you actually checked the pH? It might be low, but not low enough. The symptoms you describe definitely points to high pH. I use a pH tester pen, put soil in rainwater or distilled water, stir, wait a bit, then measure. It comes out pretty accurate.

Yes, Test the pH. Even if your soil has iron it won't be available at higher pH. A pen works or pH test paper often available at pool supply places. Best is send a soil sample to the lab.

Yes, add sulphur and no more lime. Stay at least 8 - 10 feet away. If your plants are chlorotic, you shouldn't wait for sulphur to work. Get some Iron Sulfate. Iron Sulfate is less effective than sulphur in reducing the soil pH, but it works quickly and supplies iron that the plants can use. I've seen plants that were severely chlorotic green up nicely in a week or two after applying iron sulfate.

Blueberries tend to suck for me in clay. If the soil doesn't drain beautifully you will get chlorosis and feeble growing plants which don't bare much.

Peat moss is inadequate to turn clay around quickly- I use forest compost- spongy and airy- mixed 50-50 with soil. You can find it in the woods under oak trees and white pines where litter can build up. Then plant on raised beds.

Meanwhile, I agree that you should be aware of your soils pH.

Thanks for the suggestions. I have tried two different pH probes and found the soil in the blueberry patch to be somewhere between 6 and 7, less acid than my lawn even though the blueberries have had pine straw mulch and Holly-Tone and the lawn has had lime.

Either the previous owners dumped a whole lot of lime in the blueberry patch, or the pH meters are totally unreliable. Probably the latter. I put up a thread about them on the Soil Forum.

Here is a link that might be useful: pH meter on Soil Forum

Try spraying the plants with some soluble iron and if they green up right away your problem is pH. I bet they don't.