Symbolism, Imagery, Allegory
This isn't exactly Eden, but the garden motif definitely pops its head in. Remember, in ancient Israel, farming was a huge part of life. Even if you lived in an urban area, you still ate food produced by farmers living outside the city. It's so Portland, we know.
Nature was intrinsically tied to religion back in the day. Religious ceremonies were harvest festivals, and if your crops didn't grow, it was because God was unhappy. That's probably why the Biblical writers often used gardens as metaphors—it was just in the cultural mainstream. Today, we do it with sports. Guess we're just a little more athletic.
Job and Bildad
The writers of Job definitely got all poetic on us—they like to compare human devotion to a garden that needs to be tended. The writers were intent on making sure that people followed the rules of devotion, and those who didn't would be punished.
Bildad describes this process of belief with a question: "Can papyrus grow where this is no marsh?" (8:11-19). After many long years in the papyrus production business, Shmoopers, we can tell you definitively that you need a good marsh. To translate, Bildad is saying that to be rewarded, you have to constantly practice devotion to God. Since Job is being punished, Bildad is pretty sure he's not super faithful.
Job's response? "I see your garden reference, and I'll raise you one more": "there is hope for a tree,/ if it is cut down, that it will sprout again/ […] But mortals die, and are laid low" (14:7, 10). Sure, humans are a part of nature, but there are some major difference. So Bildad's nature reference isn't enough of an explanation for him.
Other Garden Metaphors
It seems to us like everyone in the story uses the garden metaphor to suit their own arguments and thoughts. After all, nature is a big place, right? Lots of metaphor opportunities to go around.
A couple examples: Eliphaz says that a sinner's "branch will not be green," and that sinner's fields will lie fallow (un-nurtured) forever (15:32-35). Land is later portrayed as being tied to the fate of the faithful when Job asks of God, "If I have eaten [my land's] yield without payment [devotion to God],/ […] let thorns grow instead of wheat,/ and foul weeds instead of barley" (31:39-40). No beer for this guy.