My soil is neutral but acers do not do as well in that as they,do in a pot,of ericaceous compost. A friend has acid soil and grows superb acers. I think the Japanese varieties prefer acid soil but I also grow Acer flamingo. This loves my neutral soil. Earlier in the year I,posted about hard pruning this every spring.....this results in beautiful juvenile foliage of pink, cream, salmon, and light green 6' or 7' high and 9' across at the moment. (Hey, I know I have gone off the subject so forgive me). Here in Cornwall most of the county has acid soil ....I'm on the coast so,neutral soil...you will struggle to find better or bigger Japanese acers