From time immemorial flowers were used to control the offensive and obnoxiousness of body decomposition. No doubt this was part of the reason that flowers were used in the Shanidar Cave burials so many centuries ago.
One of the most famous funerals where flowers were used to mask the odor of decomposition occurred in 1874 when President Andrew Johnson was buried. his body was not embalmed, and by the day of his funeral his body was in such foul condition that undertaker Lazarus C. Shepard closed the casket and heaped loads of fragrant flowers on top and around the burial receptacle. The fragrance of the flowers hid the odor long enough for the funeral to take place.