As you say, ideal would be about ph6. But they are fairly forgiving. If your soil is very alkaline, it won't grow very well whatever you do, but, unlike an azalea, probably it will grow. If it is neutral to slightly alkaline, a bit of improvement of the ground around the plant will help.

pH testing is all very well if you can get a sufficiently representative bit of soil in the testing cup. For example, in my garden the subsoil is less acid than the topsoil (I say just by looking at it), and the topsoil quality varies around the garden according to the improvement done. Usually knowing what sort of soil you are on and looking around you what plants grow will tell you what you need to know. I only suggested rhodo fertiliser in the case that your ground needs a bit of improvement. If your ground is reliably on the acid side, then normal will be fine.