They grow well in a standard peat moss/sand which can be anything from 50% to 70% peat moss. There's no need to fertilize, as the plant relies on insects for food.
A native raspberry? Yes, and it tastes great! The fruit of Rubus leucodermis is 1?1.2 cm diameter, reddish-purple, and dark blue to nearly black when ripe, and can be confused with blackberries.