Think of it this way.....if your refrigerator and cupboards were all packed solid with food but your mouth was sewed shut would you get enough to eat?

The lower PH allows the plants to take up what they need. You could have the richest soil on earth but if the PH gets too high the plants decline.

I have to disagree with Drew when he says "Infrequent long waterings are better than frequent short ones"

While that is true for most plants BB are shallow rooted so more frequent applications of water keeps the upper levels of the soil most where all their roots are. Mulch helps a ton.

I don't have any experience yet growing blueberries, but in the soil I'm working with, I've been growing mountain laurel, rhododendrons, hydrangeas and azaleas. All four of them grow vigorously and flower profusely every year. I've never fertilized or done anything to the soil other than keep it mulched with leaves every autumn, and the biggest challenge these plants pose for me is keeping them in check. I thought this might be an indication that my soil already provides ample nutrition for acid loving plants, even at a higher pH than what they typically need in poorer soils.

It can't hurt to find out, I guess, what will happen when I lower the pH. I've put down the first half of the recommended amount of sulfur. I guess I'll just have the soil tested in the spring to see what the pH does and gauge how my bushes are responding.

Next spring is too early to take another soil test. The sulfur takes longer than that to show full effect. The bacteria that convert it to sulfuric acid won't do much over winter.

EDIT: I see that Eric said much the same thing while I was working on this post. I definitely second his opinion...

I'm tempted to believe that my mulching regime is part of the reason that my plants do well. As I mentioned, I currently mulch with leaves (shredded, mostly maple, tulip tree, oak, sycamore and shag bark hickory), and lots of white pine needles. I always figured this is the cheapest way to go and it mimics how nature works in this part of the world.Then again, it could be that plants do well because the soil is just very fertile. Farms in my area produce some of the highest yields in the state for corn, wheat, alfalfa and every other common crop. It actually seems like a huge waste of productive land to see so much suburban sprawl replacing farms around here (in Bucks County, PA).

Drew - yes, my hydrangeas bloom in various shades of pink.

Shazaam, come to think of it, I did notice that the blueberry bushes' roots didn't seem to have any root hairs on them. I didn't think anything of it at the time, but what you said is interesting and it sort of reminded me of something a naturalist told me when I was in the Boy Scouts. He said that a lot of the plants that do well in the PA mountains (where our camp was) would love to live in the more fertile lowlands, but they aren't often found there because other more aggressive plants simply outcompete them. According to him, many plants that thrive in the mountains live there because they can eke out an existence where other plants can't. Maybe blueberries are like that in some respects - they grow where they do because very few other things can handle what they can tolerate.
I really appreciate everyone's input!

Watch them turn blue with the addition of sulfur. No need to test PH, you have these plants! Apply an equal amount of sulfur to them and the blueberries. Once a nice blue, you're good! Really this would be a great indicator where you are. Give 6 months for sulfur to work. Reapply every 6 months as needed by color.

At my cottage we also have very rich soil from an old growth forest. The soil is black as tar. But the moisture, shade from very tall trees and water front conditions (it's an island), make it an extremely hard environment to grow anything. I have been struggling to find plants that work. I have found some. Mostly wild plants, dogwoods, and bamboo.

It's handy that I have my hydrangeas, rhododendrons, mountain laurel and azaleas all growing in the same general area of the garden because it was purely an accident I made back in my noob days. The BB bushes are right next to the rhododendron so they should make decent neighbors.

I was wondering though, since non-acid-loving plants border my blueberry patch on one side, how mobile is sulfuric acid in soil?. Is it going to stay put, or is it going to diffuse all over the place? If it's the latter, I should probably shuffle some things around so I have more acid tolerant plants next to the blueberries on that side.

I'm one who's seen thriving mulched blueberries in mid 6 pH soil- several different varieties in such sites. I don't believe any research has been done to confirm or disprove my theory because mulching usually isn't viable for big commercial operations and almost all agricultural research in this country involves large scale commercial production.

The particular varieties I have are Bluegold and Elliot. Apparently these bushes grow well in places that get really cold winters. If I hadn't gotten these bushes on a whim to save them from the dumpster, I might have gone with varieties that do well in the South, actually. Unlike most of the rest of Pennsylvania, I'm in zone 7a, and places only 20 miles or so south of me are in zone 7b. The climate here is more like the climate in Virginia or Tennessee - we almost never have a winter month with an average temperature below freezing. If these highbush blueberries need Michigan style cold, they aren't going to get it here. Hopefully this won't be a major complication.