The spike growth spell has a range of 150 feet, and its description states:
The ground in a 20-foot radius centered on a point within range twists
and sprouts hard spikes and thorns. The area becomes difficult terrain
for the duration. When a creature moves into or within the area, it
takes 2d4 piercing damage for every 5 feet it travels.
The transformation of the ground is camouflaged to look natural. Any
creature that can't see the area at the time the spell is cast must
make a Wisdom (Perception) check against your spell save DC to
recognize the terrain as hazardous before entering it.
When a creature casts spike growth, do they need to be able to see the center of the circle which spawns the growth? Or can the center or entire growth be behind total cover? Does the area of effect continue around corners, or pass through total cover like a door or thin wall?