Q.Why are my pink pampas grasses not growing??
We’ve cut them back in the spring, and now nothing, no sign of any green.
Certified GKH Gardening Expert
You are in planting zone 6a and the planting zones for pampas grass are 7 to 11. So it is possible it just froze out during the winter. Also, you may have experienced a dry winter, and without supplemental watering, you can lose plants.
Here is general care for pampas grass, you might see another reason it didn't come back: