A new and distinct plum tree variety, Prunus salicina, cv. ‘Suplumfiftyfour’ is characterized by having very large, juicy fruit with black skin and yellow flesh. The fruit of the new variety ‘Suplumfiftyfour’ also has a high Brix:Acid ratio, firm flesh, a mildly sweet flavor and a stone that clings to the flesh. The date of ripening of the fruit of the new variety is later than for ‘Friar’ (unpatented) and earlier than ‘Owen-T’ (unpatented). The fruit of the new variety ‘Suplumfiftyfour’ is larger than the fruit for ‘Friar’ (unpatented) and ‘Owen-T’ (unpatented).
