I have a couple of Salvia argentea 'Artemis' in one of my gardens. They like really sharp drainage, if you have clay, planting them "high" like lavander might help with the drainage. They don't seem to like the extreme heat of our summers. I planted them about two years ago and they still struggle and have not really grown much. I have extremely lean, sandy soil even with lots of amendments so they might do better in an amended clay soil. I've seen them growing in a garden in Zone 6 and they were very pretty. Maybe keeping them in full morning sun and out of afternoon sun might help also. Adele

Thanks Adele