Last year, I killed off my front lawn completely, and reseeded it
with several types of creeping red fescue. (mostly epic and boreal) I
usually don't spend much time on the lawn, and don't even water it, but
I did end up spending a good amount of time and money on it. (including
about $100 a month watering it to help it get established)

The main point was to create a low growing, low maintenance
experimental lawn that would supposedly only need mowed half as often as
our others.

While the creeping red fescue does seem to be meeting this criteria,
unfortunately, I did not notice that the "shade mix" grass seed that I
used had PERENNIAL rye in it, not the annual rye that I thought it had.
I was thinking that the rye would dye off, and the fescue would fill
in during subsequent years through the rhizomes.

Instead, what I ended up with is maybe 20% of the lawn that is fast
growing, light yellow-green coarse blades that are almost twice as high
as everything else in a week. In effect, it looks a lot worse than the
lawn I had before I tried all of this.

Is there anything I can do to kill off the perennial rye that is
mixed in, without killing off all of the red fescue? I really don't
like the perennial rye, but also don't want to completely start over
again. Help!