Originally posted by Faceplant8:

Now I'm wondering if other trees might grow in mountain or swamp. I think I've planted everything in plains, but not mountain or swamp that I can remember. I suspect it's not going to work, but I might have to try it to be sure, unless someone else can confirm one way or the other.

The only thing that will grow in Mountains is Fir trees.

The only two things that can grow in Swamp is Turnips and Seed Turnips. (No trees.)

Beech, Birch, Pine, and Oak will grow in Meadows, Black Forest, or Plains.
Fir can grow in all of the above plus Mountains.

Turnips, carrots, and onions can all grow in Meadows, Black Forest, or Plains. Turnips can additionally grow in Swamp. Same with their seed varieties.

If you want a handy-dandy chart, see the Cultivator[valheim.fandom.com] page on the Wiki.