It could be a ph related issue. Most compost are peat based but they might contain lime unless they are specific for ericaceous plants. Have fertilised it at all ?

I fertilized with a generous handful of hollytone at planting. I also topped with a little of Espoma soil acidifier, but have heard that takes a while to be effective.

It sounds like you took all the right steps then. Hopefully someone else will chime in and shed some light.

After a little research, I would suspect iron deficiency. See here: Iron Chlorosis.

The bush is looking pretty good. Blueberries are known to show iron or nitrogen deficiency that is usually caused by pH problems or cold weather. As long as the majority of leaves are dark green, the bush should grow out of it. It sounds like you are doing everything that needs to be done. Warm weather and time should correct the problem.

I may start adding a splash of white vinegar in the watering can to help with the ph as the soil acidifier breaks down. I'm also considering getting a ph test kit to make sure ph is the problem.

If it is a ph problem, I have used agricultural Sulfer to correct it on the advice of a commercial grower. He also said to use an acid base fertilizer.

Wanted to follow upon my Chandler Blueberry with the discolored leaves. Today I came out to water and noticed some new and different discoloration. Some of the leaves are developing brown patches. These spots are dry and crispy looking. Does this look like a separate issue? I've added a little more Espoma soil acidifier as a top dressing over the past couple weeks and have been adding a splash of white vinegar to the collected rain water when watering. As you can see, this is not affecting the majority of the leaves, but the ones it is affecting look pretty bad. All advice is appreciated!

It's been too long since I grew them in MO., but I do remember that they would tend to dry up if not kept well watered. They have a very shallow mass of roots and are not happy in hot dry weather if not kept really well watered. If you have lots of peat moss, organic matter, etc., that would hold moisture I would think they would be doing better at this time of year. Our native soil Ph was about 6.5 and we were told to use 1 Cup of agricultural sulfur per square yard of row by the pick-your-own grower we got our plants from. We did that in addition to adding lots of peat and composted pine bark needles. Then kept them well mulched with hardwood lathe turnings from a local handle factory.... probably hickory. We laid out a permanent drip irrigation line in the row and grew lots of blueberries for as long as we took care of them. They are not normally bothered by many pests or diseases. The main issues with blueberries is water and the correct Ph.

I am no expert and struggling with my own blueberry plants but have some discoloration similar to your first pictures. I had my plants in a mix of 1 part pete, 1 part sand, 1 part miracle gro potting mix.

Growth has been very slow/non existent last year. Even had a couple die. This year when the woke up the are very weak and have coloring like yours. I started to think it was nutritional decency from ph being too high. I tested the PH and sure enough it was 7.

Just this weekend I transplanted all plants to Al's 5-1-1 mix with no lime. I have also added 1/2 dose of osmocote.

Here is a good read on Al's 5-1-1 mix:

http://forums2.gardenweb.com/discussions/1423691/container-soils-water-movement-and-retention-xvi

I purchased Ammonium Sulfate and Sulfuric acid and plan on using using them as prescribed by FruitNut here:

http://forums.gardenweb.com/discussions/1462273/one-and-7-yr-blueberry-growth-with-pictures

Good Luck! Send us an update.

Thanks all, I will keep you updated. This year is my first time growing blueberry (4 plants so far) and I'm hooked! I'm going to try to water more frequently, didn't realize that underwatering could be part of what is stressing this particular plant. It has been unseasonable hot (high 80s for a bit) and this bed gets direct sunlight all day until late afternoon/early evening. I'm so used to growing vegetables that visibly droop when they are thirsty.

Still think ph is part of the problem. Just hope this guy can hang on until it gets adjusted.

PS... My pick - your - grower told me to use triple 13 fertilizer on them because it has an acid base. Might want to check your water's Ph, also. One difference was that I had mine in amended garden soil.. not a pot.

Don't panic, its fruiting and showing new growth. BTW I would never use a 5-1-1 mix on Blueberries never for a pot. Whats the old saying you can never overwater a blueberry? Its true. I have Chandlers for over 10 years now. They do not like more than 6 hours sun. They also like a more open middle - your a little crowded. New leaf growth is always quite pale or even tinged red before it darkens. To be ignored. Your in ground Soil mix is good if you added enough peat. If you live in a hot climate the soil microorganisms may have consumed much of it already. You do thin berries right? Just sprinkle some hollytone and espoma at the plant base and use some quick fix fertilizer like miracid liquid. All these leaves will fall off anyway come fall.

I'm not sure where you live or whether you have any aphid problems, but this could potentially be your problem as well:

https://en.m.wikipedia.org/wiki/Blueberry_shoestring_virus

I have Chandlers for many years, for me its normal for this variety to have reddish tips on new growth that later turn fully green, an oddity particular to this variety. I also have never had any insect issues, it seems most insects have no interest in them.