Man has had a fixation with flowers since the dawn of civilization. They were central to ceremonious activity tens of thousands of years ago, as archeologists discovered across the cradle of civilization. On the banks of the Euphrates River, in present day Iraq, fossilized floral arrangements and traces of pollen were discovered amongst the dead, indicating ceremonial significance.
In relatively more recent times, during the Victorian Era, flowers and floral arrangements were introduced more as the language of love- especially the rose. It was during this time during the 18th century the red rose indicated deep love and affection between lovers forced to keep their feelings a secret, for whatever reason.
But the reasons the red rose is held in such high regard as symbol of passion has to do with not only the deep red color, but the thorny stem as well. The deep red coloring is symbolic for undying love and devotion and all the passion that lies therein between two people.
The red coloring indicates a promise to undying affection. It is an indication of the throbbing heat of new love and passionate expression of attraction, consummation and craving passion, but is more meaningful against the thorny stem. This is because the affection and passion the petals symbolize true love, stronger than the thorn, representative to all obstacles interfering with true love.