Yes, they do require different culture :-) Only the big whites (Zantedescia aethiopica and ctvs.) are considered fully hardy here and they prefer a rich, moist soil and will tolerate a fair amount of shade. They can even be semi-aquatic in nature.

Nearly all the colored forms you find for sale here are hybrids and with varying degrees of hardiness depending on parentage.......generally, not very :-) They prefer more sun and drier conditions (although not bone dry - normal garden irrigation is fine) and typically have a slightly later bloom period. These are typically grown and sold as seasonal plants here and are great for containers. If good soil conditions and in a mild winter or with some protection, a few of the colored hybrids can overwinter. But I would never count on it!

For the most part I only see clumps of Zantedeschia aethiopica and Z. rehmannii looking like they have been growing outside here for some years. There is also apparently variation in hardiness between different forms of the white species, judging from what I have read.

I thought a pot of one of the "black" forms on the market now, which spent the winter in a cold greenhouse had died and tossed it out the door, to be dealt with later. Recently I saw it had several inches of new growth and put it back inside. It must not have sprouted until well into July.

This post was edited by bboy on Fri, Aug 9, 13 at 20:17

I was aware that the white and colored callas needed different cultural conditions. My white callas are at the base of my retaining wall, and the colored callas are at the top of the wall. I was just wondering if the different colors had different requirements. I have a "black" calla that I keep in a pot which I put in the greenhouse over the winter. I guess maybe I should put the yellow one in a pot, and see if it does any better.

It is my understanding that the colored Z. rehmanniis need considerably better drainage in winter than normally found in the PNW and that it is all of our rain which kills them rather than the cold but I have not personally tested it. They don't interest me much though the new black ones are pretty cool. Many are grown just for potted color and not intended for garden lives...

I am aware of the drainage issues with the colored callas. They get plenty of drainage at the top of a retaining wall. My soil is quite sandy. I'm thinking at this point that the yellow with spotted leaves is a just a little more tender than the pink with plain leaves. Now, I have to decide if I want to go to the trouble of digging it up, and potting it.

I have a yellow one that I have experimented with. It has spent winters in the cool greenhouse some winters and been fine. I divided it a couple of years ago and last winter left part of it in the veggie garden. It is actually growing better than the coddled one with more flowers. Mind you we had a warmer winter and this summer has been hotter so I'm sure that has helped. The veggie garden has good drainage.

i am on the fourth season of Zantedeschia 'Flame'. in blasting west sun, very well drained slope. they don't seem to mind those conditions at all. on the years that i remember their location and get them with some fertilizer they bloom fine, but seem to like more rich conditions than i provide.

considering the west sun, and their ability to do with minimal water, pretty great plant just for the foliage.