Spirea is a versatile bush, and comes in so many varieties.  They are very hardy and can really add great color to the garden.  I have spirea planted alongside my driveway where the snow plow always pushes the piles – so youcan imagine anything planted there has to be able to take a beating.  In comes Spirea!  I cut them back to the ground each fall and each year they come back (after that mountain of snow has melted) bigger, more beautiful and very full.  Without cutting back you will eventually be left with a very woody unshaply bush.  So get out there and hack those spirea to the ground (also makes for easier fall clean-up).