Trees and Sugarcane drop performance down

I have a 16GB IPad, hardly 5GB is used. But, when I'm in a one block radius of a tree or a cane, there is a huge dropping performance. My device is not jailbroken, nor I have interfered in the game files. I never experienced this issue in 0.3x/0.4.0 . Experiencing lag in both survival and creative (both SP).

I hope it is fixed in 7.0