The language of flowers, sometimes called floriography, was a Victorian-era means of communication in which various flowers and floral arrangements were used to send coded messages, allowing individuals to express feelings which otherwise could not be spoken. This language was most commonly communicated through tussie-mussies (small flower bouquets), an art which has a following today.
The nuances of the language are now mostly forgotten, but red roses still imply passionate, romantic love and pink roses a lesser affection; white roses suggest virtue and chastity and yellow roses still stand for friendship or devotion. Also commonly known meanings are sunflowers, which can indicate either haughtiness or adoration.
Inevitably there are geographic variances.