One of the things that I've noticed with cemeteries in the northeast is
myrtle (vinca, perrywinkle, ...) which grows even if the cemetery was taken
over by forest long ago.  It is wonderful to stumble across a country
cemetery in the midst of a mature forest with 3 foot diameter maples and
still find a lush patch of green myrtle.

Another "indicator plant" that I discovered to be in cemeteries, and which
seems also to be planted, is thyme.  There is some symbolism For years I
thought the wonderful aroma was a lichen growing on the stones until I met
a woman who would go to the cemetery near her house and pull it from the
grass for use in her kitchen.  Many of the cemeteries I have studied had
thyme growing over the entire area, having spread unchecked for over a
century.  It did best in mowed cemeteries but I found it still growing in
weedy plots as well as wooded areas.  Of course I discovered this
interesting tidbit at the very end of my survey of over 60 cemeteries.

        Dan W.