I hunt a couple areas... One is ranched for cattle, and there are areas where the grass is "golf-course" short due to grazing, and the more rugged areas where the grass is a bit taller.
Another ranch I hunt is considerably larger with no cattle, and the grass can be anywhere from 1-3 feet tall.
It is my impression that the birds prefer the open areas with shorter grass... I think they want somewhere to strutt and be seen, an area where the predators cannot easily sneak up on them, and that tall grass holds a lot of moisture, and those birds get wet walking through it. If hunting areas with tall grass, I will frequently look for clearings in the woods where the grass is shorter and the ground more open, or near logging roads when hunting birds right off the roost.
I actually do have considerable success hunting that tall grass, but I tend to do better in the late morning or early afternoon, after the grass has dried, and after the hens have left the toms for the nests... I like to find a rock or a stump to set up on in tall grass (to hide behind and lay the gun on).
I have also noticed that the birds tend to come in a bit more quietly in tall grass, and you have to listen for clucks/putts, or drumming rather than gobbling.
One thing I will mention, is that the shooting can be tougher in that tall grass. When you can only see the head, it can be tough to make yourself put the bead below the birds head (basically aiming at the grass below the bird)... I have missed exactly 2 shots at turkeys, and one was last year in the tall grass, and I shot above him (only on the first shot though
). Know where your gun shoots, and know where to put that bead, when all you can see is that red head poking up...