Blightberry Bushes are naturally occurring blocks in the Nether that grow Blightberries.
The Blightberry Bush is an easily transportable block. As the name implies, they give you Blightberries. To obtain said Blightberries, simply left or right click to get them. The Blightberries can be easily seen on the fully grown bushes, as they appear as green dots. You can only harvest them when you see the Blightberries on it. When transplanted, they will need to grow to their full form to spawn Blightberries. They need to be placed on Netherrack or Tainted Soil.
You can use bonemeal on the bush to make it grow through the stages, as well as produce another bush on top once that bush is fully grown.