If you are using the sprinkler system to water your blueberries, I assume it is with your city water? What is the pH of city water? Not too far away from where you live, my city water pH is 8.6 with lots of bicarbonates and if I water my blueberries, that will kill all my plants as blueberries grow in low pH (4-5.5 optimum) and therefore, I have to acidify my city water or water them with rain water. As you might already know blueberries can not take up Iron at higher pH and turn their leaves yellow like yours. This also applies if the soil or water pH drops below a pH of 4. I would check the pH of city water with a cheap pH meter like this (http://www.aliexpress.com/item/1Pcs-Lot-PH-Meter-PH-Meter-Pen-PH-Value-Test-Pen-PH-Tester-Free-Shipping/1308772917.html) or probably Ebay or Amazon has better deal and free shipping, if you already don't have one. You can then adjust the water pH around 5 with battery acid (that is sulfuric acid) for every watering unless you use rain water. More discussion is here: http://forums.gardenweb.com/discussions/1459560/blueberry-watering-mix-vinegar-or-lemon-peel-to-acidify-water if you are interested to know. In the meantime, I would also check the soil pH every six month and adjust the soil pH if out of range.

Blueberry plants will not tolerate drying out at all. It only takes one day in dry soil to make them drop all their leaves. Once they drop all their leaves, it is pretty much toasted, unlike most other plants, it won't come back. It can, however, be saved if some leaves are still intact and green like in one of your picture above. Blueberry is a kind of high maintenance but very rewarding plant.

Agree with above poster, most of the new growth you have is exhibiting severe iron chlorosis, which is almost certainly caused by them growing in too high a soil pH (I suspect your water pH is high and it drove your soil pH up). If you are not comfortable using battery acid, or want to do some reading up on it first as there are numerous threads on here that address using it to lower water pH for blueberries, a temporary solution would be to hand water your blueberries with acidified water using vinegar (you can try 1 or 2 tablespoons to a gallon of water but that's just a guess as we don't know your water pH so a tester is recommended). No worries, get the pH right and the leaves will green right back up.

The new growth on my Rabbiteye blueberries always seem to be light green, almost white. The pH is around 4.5 to 5.0. I think as long as it is on the new growth it will green up. Make sure you are adding plenty of water and letting the water run out the bottom of the pot. If you lightly water it will build up salt.

Water in Beaumont is soft and has little bicarbonates and I am able to use city water. In fact my pH tends to be too low. I do fertilize with 1 teaspoon to 2 gallons of water of ammonium sulfate weekly. I don't know what the bicarbonates are in Houston. I would assume anything west of Houston would have high bicarbonates. If the water comes from limestone based watersheds it will have high bicarbonates.