A wide array of late blooming sub-tropical sages is now available by mail order or even at local garden centers. These bring gorgeous colors and striking form into the late garden, but like dahlias they are at their best just before the first killing freezes. The ones I've tried seem to be more frost tolerant than dahlias, and some of them will survive the winter outside if well protected. A cutting planted in May should form a three or four foot bush by October.
When they bloom seems to be influenced by the amount of sun they get. In full sun they seem to bloom a bit earlier. But the basic influence for bloom seems to be day length, and most of the cultivars I've tried are precariously late. A century ago the common cosmos of gardens, Cosmos bipinnatus, existed in gardens only as very late forms which bloomed just before the first good freezes finished them off. The cosmos forms grown now seem insensitive to day length and bloom all summer. Is some forward looking Salvia breeder working on day length neutral Salvia? Will we ever have Mexican sage blooming in the June garden?
The ones in the images here are (at the top) the Mexican sage Salvia leucantha and two forms of the pineapple sage, Salvia elegans (long grown as Salvia rutilans). The one with yellowish foliage is 'Golden Delicious' and the other one is 'Tangerine'. All of these are widely available and can be thought of as the "beginner" sages for those starting in on these very handsome plants. Because they are so readily available, it's tempting to let them freeze in the garden when the time comes, but they can be started from cuttings or the entire clump can be cut back, dug, and heeled in against the house wall or in some other protected place where there is a good chance it will survive. Or the plants can be potted up, cut back severely, and grown on in the house during the winter. Such overwintered plants produce much bigger garden plants the following year.