Has anyone seen a scientific study that supports the claim that rhizomatous tall fescue is actually rhizomatous? I've seen more than one online blogger claim that it does not spread--at all. One did a test in which he made three 1 sq ft plots--one was KBG, one was RTF, and one was regular TTF. He used a coffee can and roundup to make a hole in each plot. After one season the KBG had completely filled in the hole. The RTF and TTF had not filled in the hole at all. The RTF behaved no different from the TTF.
It was a very convincing experiment. On the other hand, though, some very reputable organizations--like Universities--are behinds these claims.
I went to a local garden center and the only RTF they had was mixed with KBG, which seems rather convenient to me.