Skyrim Sidelines- The Blessings of Nature: The Giving Tree or the Cringing Tree

When you show her the sword, asking if this is the one referred to, she recognizes it immediately, and tells you that you are no longer welcome.  She insists that you must leave, and will speak to you no longer.

Before proceeding, check the book beside her rock- it is a skill book for Restoration, which can be quite handy.

When you approach the tree, what happens depends on whether or not Maurice has actually made it to the sanctuary with you.

If he has, Maurice begs that you not harm the tree- it is sacred to him, and he wishes to pray to it.  You can choose to ignore him if you like, but that pretty much negates the entire point of bringing him here and keeping him alive.  If you allow him, he will approach the roots of the tree and kneel to make his prayer.  After a few moments of listening to him praise the tree and the blessings of Kynareth, a sapling will sprout by the roots of the tree- you can collect this to bring to Danica instead of some sap.  While this route leads to less material rewards, it’s a far less bloody (sappy?) method of resolving the dilemma over the use of the Nettlebane on the tree.

Once the sapling is sprouted and ready, Maurice will rise from his prayer, indicating that the new tree is a blessing from Kynareth, and the will of the Eldergleam to reward one who would avoid harming it.  He has no use for the sapling himself, of course, so he offers to let you take it back to Whiterun and the failing temple.

If Maurice did not survive to reach the sanctuary or you didn’t choose to bring him along, though, you have no choice- the roots of the tree are blocking your access, and you have no other way to get anything from the Eldergleam.  Equip Nettlebane, and use it to prod the roots, and they will curl up away from the path.  You will need to poke two more times to get the tree to retreat entirely from your route to its trunk, which is surrounded by still more plants you can gather for your alchemy.  De-equip the Nettlebane and ready your usual weapon from here, then approach the trunk and activate it to receive the sample of sap you need.