Euphorbia, Crested Oleander Spurge, Hedge Euphorbia, Indian Spurge Tree 'Cristata Variegata'

I have had this plant for a few years, and see it often for sale in local cactus/succulent trade... thought it was going to be one of tho...Read Morese plants I would wish I had a greenhouse for in the winter... but surprisingly cold hardy and also very sun hardy for a variegated plant. Lives in a pot totally unprotected in my backyard all summer long- no signs of sun damage, even in temps over 100F. In winter I put it on the patio, but wondering if I even need to do that. Last year handled temps into the high 20s without any problem (lost its leaves, which it otherwise has most of the year).