From the Wiki article (see below for link)
A blue flower (German: Blaue Blume) was a central symbol of inspiration for the Romanticism movement, and remains an enduring motif in Western art today.[1] It stands for desire, love, and the metaphysical striving for the infinite and unreachable. It symbolizes hope and the beauty of things.
Early use of the symbol
German author Novalis introduced the symbol into the Romantic movement through his unfinished coming-of-age story, entitled Heinrich von Ofterdingen.[2] After contemplating a meeting with a stranger, the young Heinrich von Ofterdingen dreams about a blue flower which calls to him and absorbs his attention.
Explanation of the symbol
"This blue flower is the watchword and sacred symbol of the [Romantic] school," according to H.H. Boyesen. "It is meant to symbolize the deep and sacred longings of a poet's soul. Romantic poetry invariably deals with longing; not a definite, formulated desire for some obtainable object, but a dim, mysterious aspiration, a trembling unrest, a vague sense of kinship with the infinite, and a consequent dissatisfaction with every form of happiness which the world has to offer."[3] Thomas Carlyle offered this, that the blue flower "being Poetry, the real object, passion and vocation of young Heinrich, which, through manifold adventures, exertions and sufferings, he is to seek and find."[4]
Use of the symbol
Joseph Freiherr von Eichendorff wrote a poem called Die blaue Blume (The blue flower). Adelbert von Chamisso saw the core of Romanticism in the motif, and Goethe searched for the "Urpflanze" or "original plant" in Italy, which in some interpretations could refer to the blue flower. E. T. A. Hoffmann used the Blue Flower as a symbol for the poetry of Novalis and the "holy miracle of nature" in his short tale "Nachricht von den neuesten Schicksalen des Hundes Berganza".
In 1902, Charles Scribner's Sons published The Blue Flower, a collection of short stories by Henry Van Dyke, the first two of which, "The Blue Flower" and "The Source", refer to the blue flower as a symbol of desire and hope, and the object of the narrator's search. This volume also includes Van Dyke's most famous story, "The Other Wise Man".
Blue rose
Walter Benjamin used the image of the blue flower several times in his writing. For example, the opening sentence of his essay Dream Kitsch: "No one really dreams any longer of the Blue Flower. Whoever awakes as Heinrich von Ofterdingen today must have overslept." Also in his Work of Art essay: "The equipment-free aspect of reality has here become the height of artifice, and the vision of immediate reality the Blue Flower in the land of technology."[5]
C. S. Lewis, in his autobiographical book Surprised by Joy, references the "Blue Flower" when speaking of the feelings of longing that beauty elicited when he was a child of six. He associates it with the German word sehnsucht, and states that this intense longing for things transcendent made him "a votary of the Blue Flower."[6]
English writer Penelope Fitzgerald's historical novel The Blue Flower is based on Novalis's early life.[7] In John le Carré's 1968 novel A Small Town in Germany, the character Bradfield says, "I used to think I was a Romantic, always looking for the blue flower" (Pan edition, p. 286 – chap. 17). Substance D, a fictitious drug in Philip K. Dick's 1977 novel A Scanner Darkly, is derived from a plant with blue flower.
more from Wiki article:
https://en.wikipedia.org/wiki/Blue_flower