What is blackberry preserve called?

Answer 1

Blackberry preserve, (aka jam or jelly) is often called 'Bramble' jam.

I believe this is to give a rustic, home-made feel to the prospective purchaser.

You often hear blackberry and apple pie referred to as 'Bramble and Apple Pie'.

I think the term bramble is used to refer to the fruit of wild blackberry bushes which are often found on waste-ground or in hedgerows, whereas the fruit of cultivated or farmed bushes is simply called 'blackberry'.