at leat for the Mushrooms and other plants this mod should work
https://www.nexusmods.com/valheim/mods/274

(it can spawn the spawners and you can remove them, since its the same spawners i guess its 99% safe to say that these are completly removed too. At least the middle mouse button for delete works on wild mushrooms, but i will now not sit here and wait if they respawn)
Edit: nice branches work too