xochiyoa.

XŌCHIYOĀ to flower / brotar o florecer el rosal (M) [(1)Tp.248, (1)Zp.60,229]. It is not clear whether this is the general form or a T variant. In T the preterit is formed regularly after the pattern of –OĀ verbs, but the Z form suggests it may be a -HUA verb forming the preterit as -HUAC. In this case, one would expect the O to be long. M gives the verb once as xochyoua and once as xuchioa with no preterit form. See XŌCHIYŌ-TL, XŌCHI-TL.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 329.