
Begonias can act as a perennial during mild winters though they will not survive a hot summer without water.
Cemetery Plantings
I grew up in that time when you kept the cemetery plot clean, checked on the plantings in August, and planted fresh plants on November 1.
I was able to learn which plants could survive a summer drought – and in doing so transferred some of that knowledge to gardening.
Here are some cemetery planting ideas though this cemetery has watering devices. Most woody shrubs will survive at a two to three year establishment period as will crape myrtles. Cedar Elms are the most hardy of the cemetery plants in Texas.

Mahonia in a cemetery.

Holly fern in a cemetery.

Dwarf boxwood in a cemetery.

Cedar Elms, a native Texas woody shrub in a cemetery planting.

Cedars a woody shrub in a cemetery planting.

Cemetery Plantings – Double Knockout Shrub Rose. I should go back and see if these have survived Rose Rosette disease.
You might want to check these posts out as well!