Raspberry Bushes are naturally occurring blocks that spawn Raspberries.
The Raspberry Bush is an easily transportable block. They infinitely spawn raspberries. You need to tap the bush in order for it to drop the Raspberry. The Raspberrys can be easily seen on the full-size (grown) bushes, as they appear as red dots. Only harvest when you see the Raspberries on it.
When transplanted, they will need to grow to their full form to spawn raspberries. Place them under sunlight.
You can use bonemeal on the bush to make it grow through the stages faster as well as produce another bush on top once that bush is fully grown.
Found in warm areas.