Now that we have the anima we need, we must attune the heart of Tirna Noch to the shrines of Hibernal Hollow.
Then we can bring the wildseed's nightmares into the light and dispel them.
Take the heart to the shrines just outside of Hibernal Hollow, in the Dreamshrine basin. Then bring the heart back to the wildseed to complete the preparations for the ritual.
But be careful. Minions of the Drust seem to be amassing near the grove.