Because of the ephemeral quality of flowers, as well as their illusionary qualities, the imagery employed by Fitzgerald befits his theme of Appearance vs. Reality. For instance, Daisy's name connotes the white petals of a flower with a yellow center. Just as there is a duplicity to this flower, the character of Daisy appears innocent to the enamored Jay Gatsby who makes her the object of his desire; however, Daisy reveals her corrupt nature as she callously runs over Mrytle Wilson and eschews any culpability. Likewise, the love between Daisy and Gatsby begins in a state of freshness, but ends like a withered flower.
The name Mrytle represents the evergreen shrub that was sacred to Venus, the goddess of Love. However, Mrytle Wilson is a character who does not live up to her name, either. Thus, there is a discrepancy between her name and the reality of the person that exists.
Another flower that is employed in imagery by Fitzgerald is the orchid--a delicate, beautiful flower. Again the use of this flower imagery is indicative of the theme of appearance and reality. For instance, Fitzgerald writes that a woman, known only as a famous actress is "a scarcely human orchid of a woman," is one of the few guests at Gatsby's parties worth talking to, a refined beauty rather than an illusionary one like the other guests at Gatsby's party.
Flowers, gardens and the perfection of certain parts of the natural world seem to hold a specail place in F Scott Fitzgerald's heart - and in the novel 'The Great Gatsby.' It is very telling that these are pictured in some neighborhoods in the novel, yet absent in others. We occasionally see dusty highways, tawdry advertisemnet hoardings or garish neon lights - not usually at creative productive moments in the plot. However, the vision of the emerald sweeping lawns, floaty gauze curtains wafting in the breeze and refined terraces opening out onto balmy summer vistas is a haunting memory of the novel. Even the name 'Daisy' conjures the image of a feminine dream - the gradual corruption and desecration of the beautiful and the damned and their privileged world can be compared to the wilting and rotting of a beautiful flower.
There are many reasons behind why the use of flowers occupy importance Fitzgerald's work. I think that the notion of being able to represent a fleeting sense of beauty and allure are of critical importance to Fitzgerald's premise about the social order in the 1920s. The implication of "The Jazz Age" was that the extravagance, opulence, and perception of totalizing bliss were all castles built upon the firmament of sand. They were built to conceal the hollowness of materialism, the lack of any real notion of sensibility in both economic practice and social construction. This can be seen in Fitzgerald's treatment of the American Dream with Gatsby and the preoccupation with appearances in the "flapper" crowd of Tom, Daisy, and Jordan Baker. Such elements are temporary, something that is destined to wither away. Flowers could be a very compelling image in attempting to convey this.