Yavanna was the nourisher of all the world, for her name means "giver of all fruits". She was also called Kementári which means "Queen of the Earth". She was one of the Valar and the Aratar, she was the older sister of Vana, and the spouse of Aüle.

Her gardens were found in southern Valinor where they bordered the woods of Oromë. Her gardens supplied the magical flower from which is made the nectar of the Valar, Miruvóre.

Yavanna took many forms, but when taking the form of a woman, she was tall, and robed in green. However, she was also known to take other shapes, including a tall cypress standing under the heavens, crowned with the Sun. The tree had a golden dew spilling from all its branches, its roots were in the waters of Ulmo, and the winds of Manwë spoke in its leaves.

She watched over the growth of all living things. As the mother of the harvest she planted the seeds of all plants in Arda, and made the vast forests and pastures of the world. Yavanna also created the protectors of the forests, the "tree shepherds" called Ents. Her greatest work was the creation of the Two Trees of Valinor, Telperion and Laurelin. These trees lit the lands of Valinor with their brilliance for twenty thousand years before Morgoth and Ungoliant poisoned and destroyed them. However, with her powers which brought forth the last flower and fruit of the trees, that became the Moon and the Sun. She gave a seed of Telperion to the Eldar in Tirion, which grew into the White Tree of Tirion.

She chose the Istari Aiwendil to go to Middle-earth in the Third Age. She wanted him to be a companion for Curumo.

[with further information from Lostlondwen]
Encyclopedia entry originally written by Thorongil