§ Of the Sun and Moon and the Hiding of Valinor The Silmarillion

But when at last the Valar learned that the Noldor had indeed passed out of Aman and were come back into Middle-earth, they arose and began to set forth in deeds those counsels which they had taken in thought for the redress of the evils of Melkor. Then Manwë bade Yavanna and Nienna to put forth all their powers of growth and healing; and they put forth all their powers upon the Trees. But the tears of Nienna availed not to heal their mortal wounds; and for a long while Yavanna sang alone in the shadows. Yet even as hope failed and her song faltered, Telperion bore at last upon a leafless bough one great flower of silver, and Laurelin a single trait of gold.