It is very important to apply at least 10 cm layer of wood chips (15 cm is perfect) to keep the weeds at bay. I applied a bit thinner layer on a few spots and the weeds started growing so I applied some more cover material to suppress them.
I planted 10 american Blueberry bushes in our forest garden (3 different sorts for cross-pollination). I first dug 60x60cm holes, placed Rhododendron soil in and mixed it with some clay soil (but not much)
Once the Blueberries were planted I watered them good. Will have to water a few more times this week.
And at the end I mulched the bushes with wood chips to suppress weeds and to conserve moisture.
Lets see how they do next year :)