Last summer, Daphne gave me some Peter's Purple Monarda to try out in my yard to see how it did. Here is my report.
As I am a nerd, results are nothing if they can't be quantified. So, first, the measuring aparatus - as you can see, this thing is about 15 inches tall. This is important to remember.
In my "full sun" area, this monarda has been in the ground the longest (since last summer) and is approximately 30" high. This area doesn't get watered very frequently (I have yet to water it this year). The monarda hasn't really spread like I had thought it would, and now the parsley has taken up residence in the area where I want it to spread to...when the butterflies (and the resultant caterpillars) are done for the year, then I'll remove the parsley. This area doesn't dry out as quickly as the front bed, but it also doesn't sit in water when it does rain (like the rain garden)
In my "part sun" area, the monarda is in full bloom and has spread prolifically and is about 45" high. The monarda has been planted since last fall and gets watered somewhat more frequently than the other bed (if only because I've got more new plants in this bed that require water to get established). This bed dries out relatively quickly because it's not great soil and is elevated in a berm.
Lastly, we have the monarda in the rain garden (which is absolutely full sun - the other location is in quotations because I can't guarantee that it actually is full sun because I hardly check that area throughout the day whereas this area is in a location that I see every time I go out in the back yard). It was the last planted monarda (as in earlier this year), and is probably only about 20" tall. As this is the rain garden, it does mean that when this spot gets water, it gets a bunch of water and there were a few times when the plant was little that I questioned if it was going to make it, but now that it's taller and isn't completely covered with water, it's been doing wonderfully. The other plants in this area are artemisia (in a high ridge), and gregg's mistflower. Note: None of these plants are usually recommended as rain garden plants, but I had them on hand (as I have them growing in other spots in the yard) and decided that the worst that could happen would be they died.