Magnolia grandiflora or rose, which is an itchy tree?

Ziwei, also known as skinless tree. The bark of Lagerstroemia indica is very smooth. If you scratch the whole plant, it will swing, and it looks very afraid of "itching". Because when scratching branches, the vibration caused by friction can easily be transmitted to the top branches and flowers through hard branches, causing shaking, which will gradually accumulate and the amplitude will become larger and larger.