How high is too high? We cut all of ours at 3-3.5"
I would say a couple inches...you see how it is rolled over well you know it is too high. As long as you really watch your mower height you can get away with it being higher. But....if you go below the green part then you have an effect call "sheeting" and that spot won't come out until next year. Mine is not sheeting but just ran out of water.