Origanum sipleum

This is the third time that I'm trying Origanum sipleum (not sure of the spelling), a Turkish oregano. Each time I am enticed by the moody, dusky purple bracts of the fall plants at Agua Fria nursery. The first time, I planted a couple plants in my (relatively) protected courtyard, and the plants had severe winter damage by the following spring. They recovered acceptably by summer, and produced a nice crop of bracts, which were green, not purple. The following winter resulted in severe winter damage and the plants were removed. I bought another plant, of the darkest, duskiest purple I could find, planted it in a similar spot, and a similar thing happened. Green bracts, winter damage. This last time, a plant was planted in a pot on the north side of the house - harsher conditions yet. I expected complete death of the plant, but was surprised to find no winter damage. Many bracts have appeared, which although more colorful than the plants of previous years, are still not the dusky purple that I purchased. Maybe with cooler weather the bracts will color more. Or maybe the plants need even more drought stress. Or maybe the weather difference between here and Santa Fe makes the difference.