The mint transplantation was successfully accomplished yesterday afternoon. Peppermint on the left, chocolate mint on the right. I'm cautiously optimistic that no pieces of chocolate mint were left behind- I excised a large chunk of soil from the half barrel to try and avoid breaking off any buried pieces of stem.
Now they can go as wild as they want. The bigger the better, in fact. Both these mints are great in tea, and I will be drying as much as possible.
We filled the bare spots in the half barrels with a cheap six-pack of red and purple annual salvia (on the left with the Jackmanii clematis) and a cheap Salvia farinacea 'Victoria Blue' (on the right with the Princess Diana clematis). Victoria Blue is listed as a tender perennial (Zones 7-10), but has been reported to sometimes overwinter farther north (and/or self-seed). I'm in Zone 6a, so we'll see.
It's a big relief to have the mint out of there. I actually had a nightmare about rampant mint in the wee hours of yesterday morning. It was growing up through the floor, the drain in my kitchen sink, and covering my counter. I kept picking it and making tea as fast as I could, but it was growing faster than I could pick and was wrapping around my arms. I woke up in a cold sweat.
My subconscious is perhaps a tiny bit overdramatic.