Cold and wet can lead to red leaves. With that much rain recently I think all you can do is wait for warm weather. Maybe someone else will have a different idea but that's my thoughts.

I'd bet that it is the cold too. Mine always start out redish colored and after the 1st week of 70 degree weather they start turning green.

If you have a lot of mulch around the bushes, that will be keeping the soil cold too (works like an insulator). I pull back the mulch a little so the sun can help the soil warming process.

I sure hope its just the weather. We have had some nice weather though, its just been inconsistent. When the bushes arrived they were with green leaves. They were sent from a nursery thats a whole zone beneather our zone 6. So the redness has occured after they were planted. Its just taken a month for its to change.

3 possibilities:

1. Too much water leaching nitrogen out of the soil, so you need to add fertilizer (make sure it's for acid-loving plants! Blood meal is good, won't raise the pH).

2. pH is too high, so add some peat moss around the plants.

Did you test the pH of the soil in the holes before planting? If soil right around the plants (not sure how close you meant by "at most planting holes") in the berms is 6.0, that's way too high for blueberries! Pine needles as mulch is good, regular compost will be too high in pH. I don't know anything about cotton burr compost.

3. Plant is just stressed from being transplanted, esp. if coming from different zone. Nothing to do but baby it, check N and pH, don't overwater (blueberries don't like to be soggy) but don't let the shallow roots dry out. Some types are more drought-resistant than others, what variety did you get?

I'd call the nursery you ordered from and ask them for advice.

Its normal for blueberry leaves to turn red in the spring, if the soil is too cold. If possible, it is better to transplant blueberries when they are dormant, in the early spring. This gives the roots a chance to develop before the leaves emerge, and begin to demand water. It takes about one year for granulated soil sulfur to be metabolized by soil bacteria. Sulfur is not an acid, the bacteria have to metabolize the sulfur, and slowly turn it into sulfuric acid, which lowers soil pH. If your irrigation water is from a limestone aquifer, it will contain calcium carbonate, and the pH of the soil in your blueberry beds will slowly rise. Do you have hard water? I don't think that heavy rainfall will have an adverse affect, unless the water is ponding. Blueberries do not grow in standing water.

OP is the same zone as I am (maybe warmer). My blueberries are already starting to flower. No red leaves. Maybe it's b/c they came from a warmer zone?

Thanks for the great tips. I use ONLY rain water for drip irrigation. I did run well water through the line one time just for a test run after installing my drip system.

Yellow leaves with green veins is an iron / magnesium defficiency...Probably cause from all the rain leaching every possible micro nutrient out of the soil...I have had over 45", yes 45 INCHES of rain in the last 3 weeks with more on the way...After the rain gets outta here in a few days, take the time to put about 2 tablespoons of slow released fertilizer on each plant and add 2 tablespoons of Epson Salts(Magnesium) to each plant about 8-12 inches around the plant and scratch it in to a depth of a couple of inches...See if that doesn't help...As long as your ph is correct this will solve your problems..that is if the rain lets up..lol...On a new planting I would get your PH down in the 5.5 range at most...Younger plants are more sensitive than established ones..The reddish leaves are just from the cooler weather..Once we get hot and drier, they will green up....Hope this helps..

Using soil amendments that are not fully composted can lead to temporary micronutrient deficiences and uptake problems. In addition to a light feeding and waiting things out, lay down a thick acidic mulch of pine needles or sawdust. The plants will say ahhhh.

Blueberries don't need much nitrogen, and sawdust is a good mulch for them but first check if all the rain has leached too much N from the soil since the bacteria that breaks down sawdust (woodchips, etc.) will steal more N from the soil.

Epsom salts may be a good idea but I don't know how much Mg blueberries need - they actually thrive in poor soil!

This link may help - good pix, notice the red/purple leaves on the Mg deficient plant.

There was another U of MI page that said "Nitrogen shortages are common in blueberries. Symptoms include reduced shoot growth, fewer new canes, and pale green (chlorotic) leaves. Chlorosis is uniform across leaves with no mottling or pattern. Leaves of deficient plants often develop fall colors and drop off early. Yield is usually reduced."

Don't know why the page on nutrient deficiencies didn't say the same thing about N and "fall color".

A soil test might be a good thing.

Here is a link that might be useful: U of MI article on blueberry nutrient requirements

Sorry, don't know how to add more than 1 clickable link to a post.

Here is a link that might be useful: MI state (MSU) blueberry homepage