Some yuccas I have noticed, change colour in the winter. Of course yucca Gloriosa variegated and Aloifolia variegated change to pinkish red. I do have those... really should've taken some pics to illustrate my point.
Maybe you all have pictures of how other plants you have change colour in the winter. Post as you wish. There are these:
This plant has stood out to me in my seed grown Yuccas. Three years now, its margins turn this brilliant red, but not the margins of its brothers planted from the same batch of seeds. A keeper for sure! Y. thompsoniana...
<a href=" http://www.flickr.com/photos/seedscanada/8377817403/" title="Yucca thompsoniana win 1 by seedscanada, on Flickr"><img src=" " width="474" height="640" alt="Yucca thompsoniana win 1"></a>

<a href=" http://www.flickr.com/photos/seedscanada/8378894278/" title="Yucca thompsoniana win 2 by seedscanada, on Flickr"><img src=" " width="478" height="640" alt="Yucca thompsoniana win 2"></a>

And upon further inspection, seed grown, garden planted Yucca pallida doing the same thing. These are a year old. A much faster grower than Y. thompsoniana.

<a href=" http://www.flickr.com/photos/seedscanada/8377816523/" title="Yucca pallida winter 1 by seedscanada, on Flickr"><img src=" " width="478" height="640" alt="Yucca pallida winter 1"></a>

<a href=" http://www.flickr.com/photos/seedscanada/8378893582/" title="Yucca pallida winter 2 by seedscanada, on Flickr"><img src=" " width="478" height="640" alt="Yucca pallida winter 2"></a>