Phenology: How Tall Can Ladies-Thumbs Grow?

For years I thought of Ladies' Thumb as a native grass that didn't need mowing...but although it doesn't bloom until it gets some sunshine, this plant has been growing thick and tall in my yard on all the wet weather we had from April through August. Some years I do trim it back around the paths. This year I let it grow as high as it wanted to grow, in order to make it easier to tell when anything bigger than a cat had been in the yard...we've had some trouble with poachers and trespassers in the neighborhood. (I trust Gulegi to take care of any other snakes.) And before Sunday's rain beat it down, this is what the front yard looked like:

Unfortunately the digital camera doesn't show how tall this non-native ornamental grass is. The whole yard was about three feet deep in it. Ladies' Thumb tends to sprawl on the ground if it's not propped up by other things, so even the three-foot depth doesn't accurately reflect the size these plants reached. A few stalks that were braced against a bush had flowers growing up almost five feet off the ground.

And when it all bloomed, the whole yard was pink like this (the pink blurs in the background of the photo). Not a suburban lawn look, for sure. But pretty.