Cold hardy caladiums in zone 8a

When I moved here several years ago I was told that caladiums couldn't survive our winters and needed to be dug up each fall. Last fall I forgot to dig up all of my caladiums, and to my surprise and delight they returned in mid May even more vigorous than last summer. I've noticed they're all red, and I'm wondering if some varieties are more cold hardy than others?

That is a good observation. It would seem that the ones with more white in them have less chlorophyll to make and store energy so perhaps the bulbs are less vigorous in the long run.

Can you post a photo of your red ones?

I had mondavilla come back in my yard. One in the ground (heavily mulched) and one in a large pot. They are up and growing vigorously (no blooms yet).
The on in the ground is planted next to a large stump. The pot is next to a south-facing brick wall.
The microclimates there must be much warmer in the winter than our zone rating is.
Do you have some sort of large heat-sink structure nearby?
Lorie

Thanks for your input. Ardesia, I will get a pic online as soon as my nephew returns home from his church mission-let's just say I'm not a computer whiz. Pyromomma, my caladiums are growing in the filtered shade of a decidous oak, and they are out in the open with nothing that would create a microclimate. Since I forgot they were there, they weren't even mulched. I'm in a cold, rural part of northern Sumter County. On our coldest day last January temps here stayed in the 20's all day and dropped to 10 degrees overnight. Again, I'm amazed that they survived!

A couple of years ago I had a white caladium come back under deciduous trees in dry shade...I really think I just got lucky and it was a freak thing. It never grew to get very big, not as big as the year before and I haven't had similar experiences since. My hypothesis is that it must have been dry enough not to freeze that year in that particular spot

I have planted caladiums all over my yard, and they have never come back.

I have just planted them around my porch this year, because of this.