also depends on which species you are using. the temperate sphagnum found in certain areas will go dormant, where as those found in tropical environments will not, and might possibly die if exposed to conditions that their temperate cousins snooze in.
have never seen the ones indigenous to Hawaii go dormant. But where they exist there isn't enough cold to force them there. Have no idea how they do in other locations. However one is a common sub arctic species so it might have retained the "hard code" to do the trick, dunno
I definitely think that temperate sphagnum needs a dormancy to grow and live healthily for many seasons. I've noticed that my moss that I get locally and grow my Nepenthes in grows quite vigorously for a few months but it generally becomes etiolated and less dense. Then after this period of growth it gradually dies back to a very stunted unhealthy looking growth pattern.
In short: yes, temperate moss should go dormant in the long run.
It typically doesn't need dormancy for a long time. The Sphagnum I grow is mostly from Virginia and has been growing fine without dormancy so far. Another way to make Sphagnum go dormant is to dry it out. It's a remarkably hardy moss and I've seen several large clumps of various species go bone dry and rehydrate easily when it rains again. Some species actually thrive in drier conditions.
Thanks guys for the answers. Been away for a while and missed your replies.
My moss just appeared in my pots. I guess it started growing from spores in the growing mix. I have my Sarracenia still outdoors. We have been getting fairly mild weather so far. Just a few frosts. The moss still looks pretty good.
I plan to take the plants to their winter home tomorrow. Temps down to 28F min for short periods, full sun. They will be in an unheated greenhouse. I suppose this will be cold enough for winter dormancy?