Can you recommend a perennial that would do well at a cemetery plot in full sun. We are Zone 5 and the plot is in the middle of cemetery area with no shade, and would only have rainfall for water.
There are many drought tolerant perennials that prefer full sun.
Drought Tolerant sun loving perennials include the following: Achillea (Yarrow); Anthemis (Perennial Marguerite Daisy); Arabis (Wall Cress,Rock Cress); Aster (Aster, Michaelmas Daisy); Aurinia (Perennial Alyssum); Baptisia (False Indigo,Wild indigo); Nepeta (Catmint); Coreopsis (Tickseed); Dianthus (Pinks, Carnations); Echinacea (Coneflower); Rudbeckia (Black-eyed Susan); Verbascum (Mullein) and Verbena (Verbena).
This is from the pamphlet about perennials that are drought tolerant by the Toronto Master Gardeners. Here is a link to the guide with many other possibilities.
Personally, I have overcome this same problem by purchasing a potted succulent garden (some succulents flower in an attractive manner when they mature and are not watered) from a garden centre in spring. I put the succulent garden on the cemetery plot and have not had any problems for the last couple of years. This is not for everyone.