Plum blossom
梅 ume

Plum blooms first, in the cold, so it stands for perseverance, integrity and new beginnings; a New Year and early-spring motif.
Nara period, imported from China
Plum trees came from China and were the prized flower of the Nara aristocracy: the Man'yōshū has about 110 plum poems against 43 for cherry, and flower viewing originally meant plum viewing. Plum is tied to Sugawara no Michizane, the scholar deified as Tenjin, god of learning. As one of the 'three friends of winter' and the first flower of the year (hanafuda's February card), it became a New Year and crest motif, as in the umebachi crest.
Tenjin shrines hold plum festivals; students pray there before exams.