Abstract: Present study was conducted to study the differences in flowering behavior of twenty different ornamental winter annuals, mostly used for landscaping purpose under different agro-climatic conditions, in the Terai region of West Bengal, India under open field and protected condition. Flowering parameters such as Days required for flower bud initiation (FBI), Days required for flower bud development (FBD), Days required for blooming, Days required for wilting of flower were recorded in each plot and their average was calculated. Calendula officinalis showed earliness in FBI (23.25 DAT), FBD (32.88 DAT), blooming (35.50 DAT) and wilting (43.00 DAT) under open condition and the late flowering was found in Antirrhinum majus (74.67 DAT), whereas, the delayed wilting was observed in Helichrysum bracteatum (94.30 DAT) both under protected condition. Iberis umbellata required minimum time period (6.17 days) to reach flower bud development from flower bud initiation stage. The shortest period for wilting of flowers was recorded in Eschscholtzia californica (2.00 days) under protected condition, while, Helichrysum bracteatum required the maximum time period (21. 84 days) from blooming to wilting.