Conjurer's who do not want to disrupt the enviorment have a very cheap and pretty useful resource: air. You can use it for anything: throw dirt into someone's eyes, deflect arrows, knock people back with a sudden burst, create a tiny tornado, etc.
You could also have them restore the land after the battle, which seems like a thing they would do. That means you can be more wild with the elements.
However, let me point out that, besides the general philosophy of Conjury, there's nothing stopping a Conjurer from destroying the land for a battle. That's really up to each individual. Though being destructive -will- be frowned upon by Gridanians and other denizens of the Black Shroud.
You could also have them restore the land after the battle, which seems like a thing they would do. That means you can be more wild with the elements.
However, let me point out that, besides the general philosophy of Conjury, there's nothing stopping a Conjurer from destroying the land for a battle. That's really up to each individual. Though being destructive -will- be frowned upon by Gridanians and other denizens of the Black Shroud.