Just about everything that will grow in your yard will die off if you place anything on themespecially concrete blocks.

Many years ago, I rented an apartment, that one of the conditions of renting was that I mow the lawn. In the summer when it was hot, the owner took pitty on me and would place sheets of plastic over different parts of the lawn to kill it back so I did not take me as long to mow the grass.

We did the same thing recently and more recently decided to make it a permanent installation of stepping stones. I lifted the stones up and pulled away the mulch. While we were clearing out the dead St Augustine underneath, a blade of bermuda sprouted right in the middle. Previous to the temporary steps being put down, the area has been St Augustine for 2 years. Prior to 2014 it was general prairie grasses with bermuda. So my answer would be, no and yes (zombie grass). Having said that, while the steps were sitting down temporarily, there was no problem with the bermuda coming up around the sides.

yeah, i know there's a 99% chance they will come up the sides.

But I applied glyphosate 3x over 3-4 weeks around the concrete blocks, and the bermuda does look dead. I will observe for a while.

The bermuda I have was getting plenty of water, so I never saw any seed heads develop.

Existing rhizomes that grew in under the concrete (and were there from the start) but whose parent plants are outside the concrete range are likely to survive, unless the area beneath is so large that it chokes out oxygen from the soil.

So you can get a resprouting daughter plant from one of those because it never really was in the dark, per se, any more than a rhizome always is.

And while rhizomes do tend to be fairly short, there are certainly ones that go rather hefty distances just by random chance! They've gone under the barrier of my retaining wall with no problems to pop up on the other side, which is also three feet higher.