pruning

Question

What exactly is the difference between a spirea bush and shrub – if any? Is there a difference in pruning?

Answer 1

There really is no difference.
I will say though that often times a garden center or nursery will reference a bush as smaller with leaves that touch the ground. A shrub may be a bit taller specimen.

https://www.gardeningknowhow.com/ornamental/shrubs/spirea/growing-spirea-shrubs.htm