I was looking over the Adventurer's League module, DDAL09-08 - In the Garden of Evil (Season 9, Descent into Avernus). This adventure concerns a location in Avernus (the first layer of the Nine Hells) called Bloodroot Grove, and the evil unicorn Zhalruban who has been corrupted by the grove.
What I can't understand is what such a grove was doing in Avernus in the first place. My impression of Avernus is that it's a blasted wasteland, not somewhere where you would expect to find a grove.
Apparently, it is in some way related to Silvanus, the god of nature:
If Zhalruban has been redeemed, much of the blood-red foliage begins to turn green at the edges. Though still a corrupted oasis in the middle of Avernus, a great weight has been lifted from this once wondrous gift from Silvanus.
-- Wrap-Up: Reclamation, p. 12
Clearly Silvanus didn't decide to put it in Avernus, so how did it get here? Was it "lifted" from somewhere else (such as the Material Plane or the Feywild*), similar to how the town Elturel was taken into Avernus from the Material Plane (from the main adventure)?
* The grove might have once been in the Feywild, since there's this quote (even though it only explicitly refers to one tree):
A remnant of the Feywild, this tree is starved of light and water but still holds some its magic.
-- B10. Untainted Husk, p. 9
I assume it has been corrupted simply because it has been on Avernus for so long, since Silvanus wouldn't have created it as a corrupted grove initially, so something must have corrupted it, and being on Avernus fits as the cause of the corruption, but that further suggests my theory that it wasn't located in Avernus to begin with.
Is there any more information whatsoever about Bloodroot Grove and how it came to be on Avernus?