In zone 4, much of the answer depends on your normal winter conditions.
Areas which have reliable snow cover every year would do fine without mulch,
even with new plantings such as these. However, if your area has many cold
winter days without snow cover, and/or lots of days in the spring where the
daytime temperature is well above freezing and the nightime temperature is
well below it, the plants could get damaged, either by the absolute cold, or
by the heaving of the soil. You are probably safest to put a layer of some
sort of straw or pine needles over the beds where you have planted this
stuff late in the fall - you can even wait until the soil freezes and do it
then. Remove the stuff gently in the spring when you notice that the plants
are sending up shoots.
"Guppas" wrote in message
oups.com...
I just put in a bunch of perennials, with little knowledge of what I'm
doing and I need some general advice for the rapidly approaching
winter.

The plants I have are things like phlox, tickseed, blanket plant, some
kind of chocolate plant (named apparently for the color of it's
leaves), etc. What do I do with these things for winter? Should I cut
them down and cover them with mulch? Leave the foliage and cover them
with mulch? Just forget them until spring?

All of them are supposed to be hardy for zone 4, if that makes any
different. Any help will be greatly appreciated. Thanks!