The Medieval Garden Enclosed recently had an interesting post on the history of the pomegranate. Given its presence in myth and religion, it isn't surprising to find it in the Tarot as well. Perhaps the best known representation of the pomegranate is the RWS Tarot; notably the Empress and High Priestess cards.
The association of the pomegranate with the Empress is a natural one, since the fruit has long been a symbol of fertility. The pomegranate's appearance in the High Priestess card is connected to the two pillars, Jachin and Boaz, that stood in front of the Temple in Jerusalem and which also appear in the card. The tops of the actual pillars were decorated with pomegranates, symbols of righteousness (the fruit is said to contain 613 seeds, the number of the mitzvot, or commandments, the Jewish people must follow). Pomegranates also decorated the hem of the robe worn by the High Priest of the Temple.
This "immortal fruit" is given a place of prominence in artist An-Magrith Erlandsen's beautiful and mysterious Tarot of the Pomegranate.