A lot of home gardeners around here leave their glads in the ground. Some winters, they lose them, in other winters, they don't. It's a calculated risk. Probably worth trying, especially if you'll put mulch on. It would be a slightly better risk if you get consistent snow cover, as we do most years. I was planning to try leaving a few hundred corms in the ground this year, but am pulling out of that gardening area altogether, so I'm going to try to dig them all up after all.

By the way, a few of my glads had inexplicably twisted and curled stems this year. No pattern, just a few here and there. One is almost a figure 8. Imagine a figure 8 on its side, perched on top of a stem, and you'll get the idea. They seem otherwise healthy, so I don't know what's going on.

Jeanne

I also had a few come up that were left in the ground by mistake, but they were smaller flowers and not as long a spike as my others. It sounds very tempting as a time and labor saver, I hate digging glads up. One year I left them in my own flower bed, never to be seen again. I'm sure mulch would be helpful. Maybe leaving half or less for an experiment would be better. If it works, at least you wouldn't have as many to put in next spring. Do you sell them to a florist? That's a lot of glads!
Cheryl

Kristen,
I've had some come up each year without mulch. I bet if I had fertilized them (I don't since I usually think of them as annuals) they would have bigger blooms. Some even came up this year after the ground had been cultivated over top of them. I can't mulch due to excessive mole/vole problems. They love to snuggle in the mulch in the cold weather, and eat everything near them, completely destroying strawberries one year, so I don't even mulch the berries now. Ann