My aunt in Ohio, z5, loves callas. Every year I get a few for the patio or garden. I've had more cultivars than I can remember. The ones that I can remember are Giant Spotted (from Plant Delights), Zwartzwalder, Black Star and Flame (from Brent and Becky's) and many a mix of other colors from local retailers. They have nearly all survived the winters in the open ground 10' to 30' from the house. They bloom reliably each year. A couple have gone so far as to reseed. I took a photo if anyone is interested. There are a few varieties that have disappeared over time but I don't remember what they are as I am not there to see all of them in bloom to know their colors. I only know a few key placements and ones that still have labels (that the family kids have pulled out). I am pretty sure that the lighter purples are not there. As far as a yellow variety of Z. aethiopica and am not sure. There are some really large yellow callas that are the same size of aethiopica but I do believe they are a hybrid. John Ingram in Camarillo, CA, between Santa Barbara and L.A. http://www.floralarchitecture.com/ "Your Clivia Connection" New number >>> 805.914.9505 (cell, west coast time, please call accordingly. Thank you)