Wood hardener

I'm making a shower mat using red cedar. The last one I made out of western red cedar and after 5 years or so it started to rot at the ends. I didn't give it any finish and will probably give the new one the same treatment. I have read previous threads on shower mats and I also talked with a local slip yard.
I was wondering if wood hardener could be usefully applied beforehand to prevent rot. I may be barking up the wrong tree, so to speak, but it would seem to have some logic to it.
Does anyone have experience with this?

Options that come to mind are:

one of the anti-fungal or anti-rot paint treatments

flood the end grain with diluted varnish till it will accept no more – a recent Popular Woodworking or FWW recommended this as a finish for end grain chopping boards


ian