cypress mulch

I have a nice rhododendrum bush, I mulch this bush with cypress. I was wondering if anyone had any experience with growing in cypress wood chips.

I understand cypress is often used to build because it is resistant to rot, this in my mind says resistant to fungi as well. I use the cypress to keep the soil around the bush more acid than the surrounding soils...possibly i should switch mulches.

ive had limited luck after finding out cyprus was considered more of a hardwood. maybe too hard? bed kinda didnt flourish though.