I'm thinking this might work if you can keep it moist enough. However, I think you'll be better off to dig a hole.

I would dig the soil under the top mulch to loosen it, and add some compost to the top several inches, some bone meal or soft-rock phosphate if you have dogs that will check out the bone meal for two months. Better than peat moss is coir--the coconut husks. Peat moss kills a lot of plants from getting a bit dry; coir/dirt won't dehydrate roots so quickly.

My neighbor and I grow blueberries. He told me to mulch them each Spring with about 4" pine needles to keep the soil really acidic--add some water when the soil is drying and he does not fertilize otherwise.

Once I bought azalea fertilizer and that has helped my young plants. Maybe they won't even need that in another year. Blueberries don't have regular-type roots; they cannot have the soil around their roots cultivated. I pull weeds gently when the ground has plenty of rain water in it.

I dug up my grass put in a 1 ft raised bed filled with left over soil from my tomato buckets added compost, peat moss, and lots of pine bark fines mulched over with oak leaves and pine bark. Blueberries are like azaleas their roots are mostly in the top layers just make sure the soil underneath drains well and they get enough water.

I dug a hole, added some aged horse manure and planted the blueberries. They get plenty of water, but the weeds got a little carried away and actually covered a few plants. Finally got a chance to pull them and there's blueberries turning ripe on the bushes :)

I live in a colder winter zone, but we have hot, dry summers. My guess is picking the right blueberry for your area is the key. Here, Chippewa, North Sky and Hardiblue have all done very well, but Chippewa seems easiest to grow so far. What type of blueberries grow well in the South?