I love monarda but have real problems getting them to survive winters in my back garden. However, some I planted in a more sheltered bed at the front have come through and are growing well.
This bed is south facing and has a clay based, neutral loam soil into which a truck load of horse manure was dug about 6 years ago so is very fertile and also well drained but not dry. The monarda are in the lee of trellis panels which reduce the ferocity of prevailing westerly winds.
Monardas are prone to mildew if they are too dry but also seem to rot if too wet and they seem to be a bit nesh about my cold winters but we do regularly get below -15C and these last 2 winters have been down to -32C in Jan 2009 and -26C plus a lot more snow this year.
I wish you every success with yours.