I have clay soil here, but I also had a spot in my lawn with a huge Ponderosa Pine tree. It drops it's needles which contain lots of tannin (acid) and the grass won't grow close to the tree. I also have peacocks that roost in the tree at night, all winter long (in the summer they are locked in with the chickens, so they don't eat my garden!). The peacock poop from the tree, which is also acidic and a great fertilizer choice....so, I decided to plant all my blueberry plants in the area that my lawn won't grow, and WOW, the blueberries are in heaven, they LOVE that spot.. The spring rains wash off all the manure from the plants, and it goes into the soil, and they have all the acid they want/need. This works for me..I am guessing if you had a sunny location under a pine tree (no peacocks needed!), you might get these results too. Good luck with your blueberries.