Flowering and fruiting phenology of Acacia berlandieri, A. minuata, A. rigidula, A. schaffneri, and Chloroleucon ebano were studied at 3 sites in the Lower Rio Grande Valley of Texas from July 1998 through August 1999. Severe drought conditions prevailed for the 6 months preceding this study, and rainfall was 20% lower during the study than the long-term mean. Acacia berlandieri had the longest flowering period (5 months); each of the other 3 Acacia species flowered for 3 months. All of the Acacia species flowered in winter or spring (at relatively low temperatures and increasing photoperiod). Peak flowering occurred in February in A. berlandieri, A. rigidula, and A. schaffneri. Peak flowering occurred in March in Acacia minuata. There was significant variation in percent flowering among months within A. minuata, A. rigidula, and A. schaffneri. Significant variation in percent flowering occurred among species during February, March, and April. Chloroleucon ebano flowered in only 1 month (September) following heavy rain. All of the Acacia species dropped their fruit before new fruit were developed, but C. ebano had mature fruit from the previous year and developing fruit on the same individuals. Few shrubs or trees of any species had fruit from November through April. There were significant differences in percentage of individuals with mature fruit among species in most months, and there was significant variation in percentage of shrubs and trees with mature fruit among sites within species. Acacia minuata and A. schaffneri showed significant positive correlations between percent fruiting and photoperiod and temperature. We suggest C. ebano flowers at higher temperatures than the Acacia species and at peak or declining photoperiod rather than during increasing photoperiod.