Posted: 09/05/2017 at 12:31
I think you've answered your own question. It's dry. Soak them thoroughly, then mulch. If they're in a bit of a rain shadow too, be prepared to water more often, especially in dry spells, the late summer when buds are forming, and when it's windy.
The acidic soil thing is misleading too. They don't need acidic soil, they just don't like alkaline soil. Pete is right - you can't fundamentally change your soil. If you have unsuitable soil, you need to use large containers or raised beds to make the soil more suitable.