That's the thing. You really can't. I think that Caladiums are possibly the only genus of aroids where the stands actually DECREASE on a yearly basis, rather than increase and spread. It the breeders could solve that problem and make them more like true perennials, it would be great. People here just know that they are going to have to buy them as annuals every year. And like you said, even if you do dig them, they get smaller every year and eventually have to be replaced.
I know that there are a very few species of Caladiums that are evergreen and have no dormancy period. I have only one of those. But it is not one that could be planted out in a climate any cooler than maybe zone 10B-11+ And they are water lovers, they grow along stream banks in South America. There are also a couple of species caladiums that do go dormant every winter but do return. But none have the showy leaves of the hybrids. I think that is the trade off...showy and annual, or plain and perennial
