I have built a raised bog about 64 square feet of surface area, I'm in
USDA zone 6a in the southeastern corner of Ohio (USA). It is made of
landscape timbers, it is about 22 - 24 inches above ground level,
planting depth of about 18 - 20 inches.
It was filled with dry long fiber sphagnum moss, a small amount of leftover peat
and a few areas with added sand. I add several bales of sphagnum moss a couple
times of year to keep the plants at or above the top of the container. I
topdress around the plants with live moss when I have it and it is mulched with
several inches (3-6) of pine needles after a good hard freeze usually in
January.
This set-up has worked well in this area for the last ten years or so,
the particular bog we have at present is five years old. Our normal
temps. in winter for lows are usually around -5F to -10 F however a
couple of winters ago we had unusually cold weather with a three week
period of -30F to -45F not going above 0F during the daytimes, we did
have about three feet of snow cover which is also unusual for us and we
did not lose a single plant.
We don't have a great variety of plant material in the bog due to our
very small budget for this type of project, however it always remains
quite full and a few things are divided to make room for new material.
At present we have: Dionaea (in the sand & moss areas), S.flava, S.
leucophylla, S. minor, S. alata, S. purpurea ssp. purpurea, S. purpurea
ssp. venosa, D. filiformis and various local orchids and cranberry.
This summer we added D. intermedia and P. grandiflora, I have been told
that these should be hardy as well.
I am sorry for such a long post, I think this is probably my first to
this list, I've been around about a year now just soaking up the
information available. I hope that this reply will be of some use with
your project.
Harold W. Blazier
Dept. of Env. & Plant Biology
Ohio University
Athens, Ohio