What do flower colors meaning?

Pink Roses
Happiness, Elegance, Romance, Admiration, Sweetness, Thank You

Ranging from a subtle hint of color to deep and bright, pink roses have come to mean joy, happiness, gratitude and admiration.  They're often seen in bridal arrangements, thank you or congratulations bouquets.  Considering the word "rose" brings to mind the faint blush of a fair maiden's cheeks, it's not surprising these blooms are a favorite to give and receive.
There are many different variations of pink, from a pale blush to a gentle medium pink to a vibrant pink, each having its own meaning and implication.  The palest pink roses are a sign of gentleness, joy and grace. Bridal Pink is a perfect pale pink floribunda rose that is long lasting and offers a spicy scent.  The light to medium pink roses can show sympathy or admiration.  Lady Diana is a beautiful light pink rose perfect for either emotion.  Deep pink roses, such as Laser and Diplomat are perfect choices to show someone how grateful you are to have them in your life.

http://www.sensationalcolor.com/color-for-your-home-garden/holidays-a-occassions/the-meaning-of-the-color-of-roses.html

White Roses

Purity, Virtue, Sincerity and Chastity

It has also come to mean loyalty and faith, which can be strongly linked to purity. In true love, faithfulness and loyalty are implicit, despite distance or time. for these symbols, white roses are a perfect gift to a beloved who is far away, as they will display not only your love, but also your fidelity. White roses are also the perfect gift to send to a platonic friend, for a similar reason: constant, faithful love, mixed with the symbolism of innocence, is a wonderful way to show your love for a dear friend.

At the same time, as the uses throughout history have shown the white rose is also a symbol of strong resistance and the will to stand for one's beliefs at any cost. Giving a white rose as a gift is a very strong gift. It is not fleeting passion or romance, which is too often what the red rose conveys. The white rose is a strong and consistent love, which is pure, faithful and sacrificial. Not many flowers have such a powerful meaning to their name. And this meaning comes to the rose not only through folklore and stories, but through true histories of brave people fighting for their cause. The white rose is a beautiful flower, with beautiful symbolism, and a friend or lover should be proud to give this flower as a gift to those they love steadily and faithfully

http://winteryknight.wordpress.com/2010/06/22/what-is-the-meaning-and-purpose-of-white-roses/

Yellow Roses

Joy, Gladness, Friendship, Delight, Promise of a new beginning, Welcome Back, Remember Me,  Jealousy, "I care"

As the language of flowers was complicated and intricate, the meaning of a flower and color could be expanded on and changed by what is sent or held with the rose.  The yellow rose is often used to indicate happiness, friendship and caring but certain combinations could change the meaning to happy with the domestic life or innocent friendship. The yellow rose adds an element of happiness to any flower arrangement.

Yellow roses, with their sunshine color show the joy and happiness that friends bring into our lives and as such the yellow rose is very appropriate to send to friends.  One of the things that make the yellow rose so special is that it indicates a true friend and a true friend is a rare and wonderful gift. Always remember to include a card with thoughts that pass on the message of the flower in words spoken from the heart. The yellow rose meaning will not

be hidden in any way when you share it in your own language of love.

http://www.goldflorist.com/pages/Yellow-Rose-Meaning.html

Red Roses

Love, Beauty, Courage and Respect, Romantic Love, Congratulations, "I Love You", "Job Well Done", Sincere Love, Respect, Courage & Passion

Red roses are given to those who you want to show love and passion, people who you have great respect for, and those who have shown great courage.

The quantity can also have a special meaning. A single red rose shows love, a dozen shows gratitude, twenty-five shows congratulations and fifty show unconditional love. Two red roses tied together symbolizes an engagement.

The shade of the red has a meaning as well. Bright red means love, burgundy means unconsious love, dark crimson is used to show mourning. A withered red rose is used to show that the love is over. A red rosebud symbolizes youthful love and beauty.

http://www.thealmightyguru.com/Pointless/Roses.html