Flowers are always acceptable for birthday greeting cards.
Choose flowers in season to match your greeting card to the birthday month.
Flowers can really be used in all occasions: Mother's day, get well, thank you. When you create your own, the easiest way is to use tissue paper which is layered and overlapped to look like petals.
Years back, I got interested in the language of flowers. In the centuries past there was a whole dictionary of meanings which could be construed by people. With time passing meanings have changed and like in all areas of life, flowers have their moment and glory in turn and according to fashion. It might be that if you want to use the language of flowers again, you will have to translate in plain English at the back of the card the symbolism of you chosen bloom.
I have included in this article some of the commonest flowers. It is noticeable that as everyone uses red roses when it comes to the matters of the heart, red tulips are a perfectly acceptable alternative and red Chrysanthemum plainly scream: “I love you”.
Amaryllis – splendid beauty, pride
Arum lily – magnificent beauty
Bluebell – constancy, forgive and forget
Campanula – white, gratitude
Carnation – red - "alas for my poor heart"; striped - refusal; yellow - disdain; pink - woman's love
Chrysanthemum – red - "I love you"; yellow - slighted love; white - truth
Daffodil – regard, chivalry
Dahlia – good taste
Forget-me-not – true love, "the key to my heart"
Freesia – friendship
Garden Pink – pure love
Gladiolus – strength of character
Hyacinth – blue - constancy; white - unobtrusive loveliness
Iris – yellow - flame of love
Lilac– purple - first emotions of love; white - youthful innocence
Lily – pure and modest
Lily of the valley – return of happiness
Mimosa – sensitivity, secret love
Narcissus – self esteem, female ambition
Orange blossom – bridal festivities, virginity, "your purity equals your loveliness"
Orchid – longevity, elegance
Peony – bashfulness
Ranunculus –"you are rich in attractions"
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
Snowdrop – hope
Sunflower dwarf – adulation
Sweet pea – departure, delicate pleasures
Tulip – red - declaration of love;- beautiful eyes
Violet – faithfulness, modesty
list from the flowers association