There are no reports on plant growth regulators (PGR) or polyamines being used to stimulate bract longevity in bougainvilleaspecies, yet understanding how PGR and polyamines infl uence bougainvillea bract phenology is important for fl owerprofi tability. Potted bougainvillea plants in four diff erent bract development stages based on bract diameter were pre-treatedwith salicylic acid (SA) at a concentration of 0.5 mM combined with 1-naphthaleneacetic acid (NAA, 0.13 mM), gibberellicacid (GA, 0.29 mM), and 6-benzylaminopurine (BA, 0.22 mM) in 100 mL mixtures. Three 100 mL polyamine treatments[diamine putrescine (Put), triamine spermidine (Spd), and tetraamine spermine (Spm)] at 1 mM were also individuallysprayed on bougainvillea bracts. Control bracts were sprayed only with water. Diff erent PGR combinations and singlepolyamine treatments acted diff erently on bract longevity and endogenous 1-aminocylopropane-1-carboxylic acid (ACC)content, and each combination and single polyamine was not equally signifi cant in regard to coordinating a response toACC regulation. In combined chemical treatments, maximum and signifi cantly prolonged bract longevity in all stages weredetected in the SA + NAA + GA + BA treatment compared to controls and other combinations, and longevity increased asbract stage progressed. A strong synergistic interaction was observed between SA and NAA regarding bract longevity andACC levels. Moreover, Put also signifi cantly prolonged bract longevity and remarkably reduced endogenous ACC contentat all stages, this eff ect increasing as bract stage progressed compared to Spd, Spm, and controls. Therefore, the eff ects ofSA + NAA + GA + BA and single Put (1 mM) applied to bougainvillea bracts for increasing longevity in the nursery off ersinsight into re-vegetation, landscaping programs, and cultivation in gardens.