In the Southeastern United States, Kudzu vines grow so fast that it seems you can almost see them grow. Still, it is not the fastest growing plant. Which plant is?
Bamboo is the fastest growing plant. Some species of bamboo can grow more than 24 inches a day, twice as fast as the 12 inches a day for kudzu. Of course the bamboo is not growing that fast outwards, in all directions, so it does not engulf the landscape as kudzu does.