Emerson was a man who was interested in individualism, the natural world and the condition of one's soul.
Nature, Emerson's essay written in 1836...
...is a well-organized statement of his earliest idealism, showing the natural world to be a present messiah...
Emerson was not interested in what the world valued: position, notoriety or wealth. Having been raised in poverty himself, he had no illusions about the advantages of having money, but these things were not what appealed to him. One thing that Emerson valued was...
...a belief system that espouses a non-traditional appreciation of nature.
In perhaps one of Emerson's finest poems, entitled "Days," he finds himself lacking in that he is not a part of his "work-oriented culture." He chides himself for the different path he has taken as he writes of the passing of days, but values nature over "things." In the poem he speaks of the "daughters of Time" who are personified to express the passing of days—he notes that they bring to his "garden"...
...various gifts, the riches of life, which the poet too hastily rejects in favor of a “few herbs and apples"...
Emerson was a man of contemplation, a man who galvanized what would become the Transcendentalist movement in American literature. The value of American individualism and the search for understanding self was stressed.
...transcendentalist literature also promotes the idea of nature as divine and the human soul as inherently wise.
This provides a point of reference to Hawthorne's short story. Emerson would have enjoyed the "wealth" of beautiful plants in Doctor Rappaccini's garden—but not their deadliness: an unnatural phenomenon. The veneration shown by Rappacinni's daughter for the plants would certainly coincide with Emerson's praise of the things of nature.
Approaching the shrub, she threw open her arms, as with a passionate ardor, and drew its branches into an intimate embrace; so intimate, that her features were hidden in its leafy bosom, and her glistening ringlets all intermingled with the flowers.
The individual's search of self is seen as the protagonist, Giovanni, is mesmerized by the doctor's daughter, falls in love with her, and then is wracked with doubts about himself as he realizes that she is not just a beautiful woman and a source of delightful company, but an unnatural creature with an affinity for poisonous plants—that has changed him!
...now, his spirit was incapable of sustaining itself at the height to which the early enthusiasm of passion had exalted it; he fell down, grovelling among earthly doubts, and defiled therewith the pure whiteness of Beatrice's image.
Beatrice's individuality (as she has perceived it) has developed over time based on what she knows of herself and what she has learned from her father, but not how Giovanni is ultimately connected:
...dearest Giovanni--I grew up and blossomed with the plant, and was nourished with its breath. It was my sister, and I loved it with a human affection...
For Emerson, there would need to be a purity in nature, and a clear sense of self. The doctor has defiled nature. Giovanni loses himself—becoming another element of Rappacinni's work; Beatrice is forced into isolation—and death—by her father's unnatural "science" as she finally searches for a sense of where she can fit into a world apart from the one her father has forced on her.