In this study, for the environmental development, the antifungal, antibacterial, and antioxidant activities of a water extract of flowers from (Labill.) H. L. Wendl. were evaluated. The extract concentrations were prepared by dissolving them in 10% DMSO. Wood samples of were treated with water extract, and the antifungal activity was examined at concentrations of 0%, 1%, 2%, and 3% against three mold fungi; MH352452, MH352450, and MH352451 that cause root rot, cankers, and green fruit rot, respectively, isolated from infected L. Antibacterial evaluation of the extract was assayed against four phytopathogenic bacteria, including and , using the micro-dilution method to determine the minimum inhibitory concentrations (MICs). Further, the antioxidant capacity of the water extract was measured via 2,2'-diphenylpicrylhydrazyl (DPPH). Phenolic and flavonoid compounds in the water extract were analyzed using HPLC: benzoic acid, caffeine, and -coumaric acid were the most abundant phenolic compounds; while the flavonoid compounds naringenin, quercetin, and kaempferol were identified compared with the standard flavonoid compounds. The antioxidant activity of the water extract in terms of IC was considered weak (463.71 μg/mL) compared to the standard used, butylated hydroxytoluene (BHT) (6.26 μg/mL). The MIC values were 200, 300, 300, and 100 µg/mL against the growth of , , , and , respectively, which were lower than the positive control used (Tobramycin 10 μg/disc). By increasing the extract concentration, the percentage inhibition of fungal mycelial was significantly increased compared to the control treatment, especially against , suggesting that the use of flower extract as an environmentally friendly wood bio-preservative inhibited the growth of molds that cause discoloration of wood and wood products.