k dutch iris, hollyhocks,n shastas im wondering if you have a critter eating away at your bulbs roots or seeds?
maybe dig in your soil a bit n see if you have alot of grubs or other bad bugs, keep an eye out for squirrels, chimpmunks, moles,mice

My various plants do that sometimes. I had several long-time plants not come up last year. I thought they were dead, but then this year, there they are! As big and beautiful as ever.

I see you're in PA, so you probably experience the same weather I do (somewhat) here in Ohio. The winter when a bunch of my plants didn't come back was when it got down to almost -30 degrees. I think that hit them pretty hard and they took a whole year to recover. So, I think it depends sometimes on the winter climates' affects on the roots. Plus, it's been unusually cool here, and a lot of plants are growing and blooming late because the heat they need just isn't there.

Another thing you might try is when you cut the plants down for winter, let them dry out and then leave a good 12 inches of stem and leaves on there. Don't cut them all the way down to the ground. An old gardener taught me that trick, and it works! It helps insulate the core of the plants from the snow and cold like extra insulation, plus it gives the beneficial insects a place to hide all winter.