Persephone had ate the pomegranate the food of the Underworld.
Every year when Persephone returns from the Underworld her mother Demeter allows Spring to return to the earth.
In the myths, Demeter (Persephone's mother) is the goddess of agriculture. The coming and going of her daughter Persephone from the underworld changes the season. As you can guess, when Persephone came back to earth it was summer while when she was at her husbands (Hades) side up on Earth it was winter.
It isn't really Demeter who saves Persephone, but Zeus. After Persephone is abducted by Hades, Demeter (the goddess of the harvest, and mother of Persephone), begins to neglect her duties. Humans begin to go hungry, so Zeus sends Hermes to the underworld, to talk to Hades. (Hades gives Persephone back, but she has eaten in the underworld and must return for a period each year. This myth explains the winter.)
It isn't really Demeter who saves Persephone, but Zeus. After Persephone is abducted by Hades, Demeter (the goddess of the harvest, and mother of Persephone), begins to neglect her duties. Humans begin to go hungry, so Zeus sends Hermes to the underworld, to talk to Hades. (Hades gives Persephone back, but she has eaten in the underworld and must return for a period each year. This myth explains the winter.)
Accounts of Persephone's rescue differ. Some say that it was Hermes that took her from the underworld back to her mother. Others say that it was Hermes who tricked her into eating the pomegranate in the first place. Some even say that it was Hecate, goddess of dark magic, that took Persephone back to her mother. One thing they all agree on, however, is that Demeter was the one who negotiated Persephone's release.
Hades was promised by Zeus that he could take Persephone as his wife. But Zeus neglected to inform Persephone or Demeter (Persephone's mother) of this. So, Hades sprang up from the earth and abducted Persephone, to take her with him back to the Underworld.
Hades abducted Persephone, Demeter her mother went in search of her and her duties were neglected and humans started to starve, then Demeter learned where Persephone was and demanded her daughter back and Zeus agreed so long as Persephone had not eaten or drank anything while in the Underworld, but she had; so Persephone spends half the year above the earth with her mother and half below with Hades her husband.
When Persephone leaves the Underworld, her mother Demeter allows the earth to grow again and blossom into Spring.
Persephone ate of the pomegranate; a food Hades gave her in the Underworld; so she spends half a year in the Underworld and half with her mother Demeter.
Persephone was the personification of spring. She was the daughter of Zeus and Demeter, the goddess of plants. Hades stole her from her mother and took her to the Underworld. Demeter reacted by allowing all the plants to die until she got her daughter back. Zeus finally made Hades return Persephone. However since she had swallowed six seeds, she had to spend six months of the year with Hades and the other six she would be with her mother. So that is why most plants die in winter.
Hades asked his brother Zeus if he could have Persephone for his bride, to this Zeus agreed without consulting Demeter or Persephone - Hades than took her, and Demeter showed her wrath until she got her daughter back, except Persephone had eaten of the pomegranate and had to return to Hades for half the year, this causes Demeter to make the land cold and barren (i.e. winter). Persephone return brings about spring.
Demeter, her mother, demanded it: or no living thing would grow. Now half the time Persephone is in the Underworld it is winter, and when she returns it is spring.