If I can get some small raised beds going, I will be testing S. stolonifera as well as the recently proven hardy S. lineata and S. clinopodioidres in beds, mixed in with a fairly generous amount of pellets of expanded slate, both to deter pine voles and to provide aeration that many tuberous sages seem to need.
The bigger you get your plants, the sooner they will bloom.. There is a technique I want to try for really tender sages. If I have a raised bed, about 2 to 6 feet wide, I plan to bag shredded leaves, not just in 30 gallon bags, but in smaller ones as well. I'll put the big bags around the perimeter, and the smaller ones in between and amongst the plants, then cover with more bags. Someone in Minneapolis - St Paul metro area did this, and kept USDA zone 7 plants alive in his zone 5 garden.