Bougainvilleas are flowering machines. Having a bougainvillea in your garden or home, either in a pot or in the ground, is always joyful due to the gorgeous flush of color. Like all plants, bougainvilleas start out relatively small, but will quickly take over the space provided for them, and then some. In spring and fall, these beauties (with the right care) will explode into a profusion of blooms, spreading their thorny branches to cover a wall completely.