The leaves of bougainvillea are thin, simple, and elliptical to heart-shaped with pointed tips. They feature entire margins and typically measure 2-4 inches (5-10 cm) in length and 1-2 inches (2.5-5 cm) in width. The leaves are green, with a smooth texture and a prominent central vein from which smaller veins radiate. The upper surface is often glossier compared to the underside, which may be slightly paler. This combination of features is critical for identifying bougainvillea.

The flowers of bougainvillea are tiny white tubular blooms grouped in threes, each measuring about 1/4 inch (0.6 cm) in length. These flowers are encased by vibrant, paper-like bracts that come in various colors such as magenta, purple, red, orange, or white. The bracts, which are often mistaken for petals, significantly enhance the plant's visual appeal. Blooming seasonally, these flowers do not emit a noticeable scent, but their striking bracts make them easily identifiable and widely admired.

The stem of bougainvillea is characterized by its thorny, scrambling green texture. As the plant matures, the younger green stems gradually turn woody. These stems can range from slender to moderately thick, approximately 0.5-1 inch (1.3-2.5 cm) in diameter. The stems exhibit a branching pattern with sharp thorns, making them easy to identify. The transition from green to woody stems is a key feature that marks the age of the plant.

The fruit of bougainvillea is a modest, yet distinctive entity, characterized by a slender, five-lobed achene. Each achene is small in size, typically measuring less than one inch (2.54 centimeters) in length, with a firm and dry texture. Upon maturity, the fruit exhibits a color palette ranging from tawny brown to greyish hues, blending seamlessly with the surrounding bracts. These achenes are encased within the vibrant, papery bracts that are often mistaken for petals, and though they may lack flamboyance, they carry the vital seeds for the proliferation of bougainvillea.