Explore the use of symbolism in the novel The Garden of the Finzi-Continis.

Themes of the novel include isolation and the desire for stasis: the self-imposed isolation of the Jewish Finzi-Continis, who fear contamination by the wider society and don't want to face change, as well as the forced isolation of the Jews by the fascists, who identify the Jews as the social contamination.
One potent symbol of the isolation of the very wealthy Finzi-Continis is, as the title indicates, their huge walled garden, where they have constructed a life apart. Except for at the synagogue, we never see the Finzi-Continis outside the walls of their garden, which functions as a beautiful prison. A symbol of their imprisoning isolation is the ladder Micol keeps inside the garden. She climbs it and invites the narrator to scale the wall on his side and join her—but she is spotted before she can get over the wall and must come down again. She is contained.
Perotti, the servant who spots and stops her, also symbolizes imprisonment, for he functions more as prison guard than servant. He is the symbol of stasis, trying to keep the Finzi-Continis from changing.
The garden—and the house within it—both show the family bringing the exotic inside their walls rather than going out to it. The garden is full of trees from other parts of the world. The family has imported a large library. This represents how they try to bring in what is good while excluding what is bad.
They isolate themselves even from each other by putting phones in their bedrooms using extension cords. Ironically, Micol sees this isolation as liberating, saying that there's "nothing better" than an extension line to "protect your freedom."
Micol and Alberto are also taking a very long time to get their degrees, another symbol of their imprisoning stasis in the garden. They don't want to grow up, which is what finishing their degrees represents; they don't want to leave their suffocating but alluring garden-prison.
More pointedly symbolic, Micol is doing her thesis on none other than Emily Dickinson, the American poet who is the emblem of a recluse. It's not surprising that she would relate to this particular poet.
While the Finzi-Continis try to suspend time in their garden and keep out such unfortunate aspects of history as the increased threat of Jewish deportation, their isolation suffocates them—and can't keep out evil. This is symbolized in Alberto's literal suffocation due to a malignant lymphogranuloma, which their isolation has not prevented. The family can afford to bring in oxygen to try to save their son, but that does no good: they can no more keep him safe in isolation than they can save themselves or save the Jews.