First of all, I’m really enjoying the game so far! As someone who is a big fan of RPGs, this strikes a lot of good points for me!
While I have a few other suggestions I may post later, one idea I had was to add scenery zones. Similarly to NPC/Monster zones, this would select an area and automatically plant the specific scenery object(s) there.
It doesn’t have to necessarily be instant, but it feels pretty tedious to go through and individually place a ton of scenery objects, especially when they often overlap and stack on top of each other.