Columnar Hornbeams Fall Marcescence

This year, all eight of our Frans Fontaine European Columnar Hornbeams are exhibiting marcescence:  the retention of dead plant organs that normally are shed.  And that's by design.  Or at least...that's part of the reason why I was drawn to these particular columnar trees.  They'll provide some additional Winter screening by keeping most of their leaves on the limbs.  These look quite a bit different than a year ago - and you can see 12 months ago here - as one of them (the fourth from the left) dropped its leaves and these have widened out a bit.    The photo above is from a different angle, but this photo below shows that same angle from a year ago.  All of them appear to be thicker and a bit taller, too.

But if you also look closely at the photos above, you might notice that there is quite a bit of brown leaves at the bases of the trees.  That's something I'm trying new this year:  using leaf mulch.  I used my mower to pick up some of the leaves around the yard, chop them up into some fines and then spread them around to try to fill in some low spots.

Below is the first slot - between tree one (on the left) and two:

And below is between tree four (from the left) and five:

I'm going to see two things:

First....will this stuff stay in place.  I didn't wet it down, so I'm just relying on it not blowing all over the place.

And second...will it decompose over the course of the Winter.  Or...at least decompose enough to be topped with mulch come Springtime.   Yet at the same time, fill in some of the gap under the fence so little Lizzie can't squeeze out.