Hi songbirdy, You should be able to lower the PH level of your soil to make it more acidic and improve the growing conditions for acid loving plants.
Dig ericaceous compost into your top soil, which is basicly a mixture of peat and sand. You could also try making your own ericaceous compost by using a product called 'Chempack Compost Maker' and follow the instructions on the pack, it will also provide all the nutrients suitable for acid loving plants.
If your soil is'nt strongly alkaline, it should'nt be too difficult to lower your PH. Chempack should be available from garden centres. Good Luck Tbird+