Last year we had six flowers, this year none. What's happened?
Certified GKH Gardening Expert
This can happen for a few reasons. If they were pruned at the wrong time, then there will be less/no blooms. I find this the most common reason. They should be pruned in late winter/early spring, right before the new growth come up. Here is an link that will help: https://www.gardeningknowhow.com/ornamental/foliage/pampas-grass/