So, I'm Looking to switch from 5e to pathfinder 2nd edition. I've read most of the rules and going through the class options at the moment and I've been scratching my head over this one for a day now.
The Leaf Druid has access to the order spell Impaling Briars (https://2e.aonprd.com/Spells.aspx?ID=475).
One of the effect of the spell is to have a Wall of Thorns spell affect the area or the Impaling Briars. Since Impaling Briars is a focus spell and focus spell are automatically heightened, would the Wall of Thorns effect also be heightened or would it remain level 3?
Good question.
Looking at other focus powers that reference spells, there are two that I can see that both (1) refer to another spell effect, and (2) that spell is one for which heightening would be relevant: Fey Glamour and Impaling Briars. (Commanding Lash also references a heightenable spell, but the heightening just increases the number of targets, and Commanding Lash explicitly just has one target.)
Fey Glamour explicitly states that the spell effect is heightened, while Impaling Briars does not. That suggests to me that the Wall of Thorns effect is intended to just be at the default level (i.e., no extra hit points or piercing damage).