From the Super Mario Wiki
Bomb Plants are a special type of Bob-omb/Vegetable hybrid that grow underground. They were seen only in a few episodes The Super Mario Bros. Super Show!, and are essentially the show's interpretation of Vegetables and the Bombs that could be plucked from the ground in Super Mario Bros. 2, combined into one item.
Bomb Plants appear in several episodes of The Super Mario Bros. Super Show!, where they are depicted as limbless Bob-ombs with long leaves. However, unlike normal Bob-ombs, Bomb Plants are not shown to be very sentient, despite having eyes. This is probably due to the fact that Bomb Plants have no body parts to move other than their eyes. Even after being plucked out of the ground, the fuse of a Bomb Plant will not go off automatically. Instead, one must tear its leaves out from the main body to trigger the fuse, much like pulling the pin from a grenade.
Despite the fact that Bomb Plants consist of elements taken directly from Super Mario Bros. 2, they were created specifically for The Super Mario Bros. Super Show! and are highly unlikely to ever appear again.