@Joseph
Leaving flowers is generally a violation of the rules in most Jewish cemeteries. Carving a sentiment or endearing name is not against the rules.
I remember taking the shamash of our heimische shul in New Haven to make the rounds of local cemeteries one August when he was too old to drive. He pointed out the Matzeva of ‘The lady with the baby carriage’ There was an engraving of a baby carriage, and a story in Yiddish about this woman who pushed a baby carriage through the poor Jewish neighborhood each erev Shabbos for decades delivering free food for the poor. She had no husband or children and the Matzeva was paid for and erected by the shul Rav who decided on the engraving.