Fasciation is something that is not really understood by scientists. But it creates cool things to happen with plants. It makes a plant’s growth go berserk in unpredictable ways, growing in a manner that would not normally happen.
It is thought that fasciation happens because of a hormonal imbalance in the plant. What causes that imbalance is uncertain. It could be a random mutation, an injury due to insect action or a disease or even a physical injury. It’s believed to be totally fluke occurrences that are not shared by other plants or even to other parts of the same plant.
Fasciation is bewildering and fascinating.