Hello,
In the depths of my local nature reserve, there is a blackberry bush that produces abnormally large, sweet blackberries. None of it's neighbours have similar atributes and for the last three years I've been harvesting this one bush for the best freezer jam you've ever tasted.

Does anyone know the best way to propagate from this bush?
I don't have room for blackberries in my garden, but I'd like to try and plant some in the wild, or maybe pass some on to some other people

I know brambles are weeds, but we are talking about blackberries that could cover a two pence piece here!