Peonies are definitely not
sensitive to being buried--when we did our back garden, we put up a garden wall of two railroad ties and filled it with soil--right on top of some peonies. Those lil blighters are still
One of the few plants that not even hazel seems to kill!
There are some plants, though, like irises, that prefer their tubers to be close to the surface... I know there are others I've...ahem....eliminated accidently by burying them, but I can't remember which ones...
There have been so many!