What is the pH of your water, and what is the pH of the soil in the pots? Blueberries need soil pH to be between 4 and 6 to do well, and they will tolerate pH between 6 and 7. Anything above 7, and they will die sooner or later.

Do you have them in the sun? If they are too shady or inside the house without enough sun, the leaves can turn pale and flabby. I assume the pots have drain holes, so unless there is standing water in the saucers, overwatering shouldn't be an issue. Were they done blooming and the blooms are just naturally wilting, or were they still in full bloom yet? Dane County is still a little cool for them to be outside yet if they have leaves and flowers, so did the flowers freeze? Up here near St. Paul, (where we still have snow on the ground and it was down to 12 degrees last night), the big-box stores often get southern-grown, potted blueberries in WAY too early. Then they often keep them inside the store with no sunlight. I have picked up a few nice just-arrived bushes that way, but I have had to keep them in a sunny window on cold days and move them outside on nice days during the day. Have had my kitchen counter full of pots on chilly nights. After doing that, one also has to acclimate the plants gradually to full sun, so the leaves don't sunburn. Finally, in late May I can plant them out. Most of those stores have a one-year guarantee, so hang onto the receipt, in case the plants don't make it. It is usually recommended to remove most of the flower buds the first year so the plant can put its energy into getting established, so don't mourn the loss of the blossoms. Too much lime in the water can cause new leaves to be yellow, but doesn't usually cause flabbiness like you mentioned. I know Dane County has rather hard water, as I lived there at one time, so add a spoonful or so of vinegar to the water to acidify it. It is worth the trouble, however, as loose-frozen blueberries are a great no-fuss snack in the off season. Northwoodswis

Charleslou, I just noticed you live in zone 9, not Dane County, WI, so most of my previous advice probably doesn't apply to you. Oh well, maybe it will help someone in the North. Northwoodswis

Could be Brown Rot????