SPIREA BUSHES CUT TO 5" ABOVE GROUND
Waseca County Minnesota
You should be able to cut back you spirea without problems. Maybe the new growth is just soft due to the weather. If you have had a lot of rain it may have just been flattened a few times. If you take a short piece of chicken and put it around them for a bit to give them some support until they toughen up a bit they should be ok. You could also use some small stakes with string wrapped around it to provide support.