The rose is seen as and considered as the most beautiful flower of them all. In Alice In Wonder Land the Queen of hearts has a rose garden which she has painted red. The rose has also been used as symbol in many different cultures and points of time in history. So there is no surprise that within the Tarot that the rose holds many symbols and meanings.
Most famously the rose is seen as love and romance as has become the mascot for valentines day around the world. A lover or suitor may give you a bunch of 10 red roses or sprinkle your bed with rose petals, for a night of red hot passion and sensuality. The rose being associated with the Greek and Roman goddesses of love, Aphrodite and Venus.
For me personally I have always seen the rose of a symbol of unification, peace, the joining together of loved ones and power. Coming from England at school we all learn about the war of the roses, where two royal families fought for the crown, the white rose of the house of York and the red rose of the house of Lancaster. Henry Tudor took the crown in the end, his mother from the house of Lancaster and his wife, Elizabeth of York, the white rose. Resulting in The Tudor Rose (above), a white and red rose.
I think it is important to incorporate historical symbolism and your own intuition to form your own reading of such a remarkable and mysterious symbol.