Pat,
Sedum is easy to root. I had one which did exactly as you say so what I did was take pieces of the variegated and rooted them. Just cut a stem, and place in moist soil and in no time it will grow roots.

The result was that I was able to grow quite a few that were completely variegated. I still kept the other plant and it still does the same thing, but now I let it grow as it pleases and it is quite pretty.

Tiffy, I would be surprised if a cutting would stop reverting to green. I expect eventually it also will show up some green growth - but let me know if I am wrong.

Pat - it is common for many variegated variety of plants to revert back to green. Trees, shrubs and perennials. Some types are more stable than others. Nothing to do but keep pinching out the green.

My gorgeous "Frosty Morn" was spectacular the first year, purchasing in a gallon pot locally, if I recall. The next year, it was green, maybe a shoot of variegated foliage. Same this year. Luckily my belief is that you can't have too many sedum, regardless of what it's color should be.

It's important to realize that it's the green part of the plant that makes energy through photosynthesis. Therefore, the green leaves and shoots are the most vigorous and the variegated ones grow more slowly.

Often, when you try to root variegated stems, they won't root, or die shortly after they do. This happens especially if the shoot was completely white. The only thing I have ever read you can do about reversions (all green) is to keep cutting them off. That way they aren't competing with the variegates and, of course, don't become a distraction to the beauty of the plant.

I love both Frosty Morn and Mediovariegata (the green and yellow form). I just wish they didn't lose their leaves and look so "nekkid" in the hot summertime. I cut them back and cut them back them back, but it doesn't help much. I always threaten to get rid of them this time of year, but they are soooo beautiful in the spring!

As mentioned, a number of variegated plants revert to plain green over time. I yank off at least a couple green stems from my plant of S. 'Frosty Morn' every year and consider that the price to pay for having the plant.

If you give your plants the best culture possible, it probably will lessen any stress-caused reversion to green stems, which as donnabaskets indicated are the most vigorous and efficient energy-producers for the plant.

Last spring I had to move my Frosty Morn, and to my surprise, the 'reverted' part completely separated from the variegated part. So I put them in two different places. It was not what I expected, and makes me think the totally green sedum was really a seedling, instead of a reversion.