Purple, blue, white, pink, or red. Cold hardy, drought resistant, deer resistant, and bunny resistant. Loves the heat and can be grown in full sun or partial shade. Attracts bees, butterflies, and hummingbirds. It will work in any landscape, from the Tropics to the Arctic.
Salvias actually are part of the mint family, with over 100 cultivars and varieties. There are annual salvias, biennials, perennials, and shrubs. Some stay quite small and some get pretty big (over 6' across and 3' tall). Salvias are readily available at almost any nursery and are usually fairly cheap. They are almost impossible to kill, surviving admirably in almost any type of soil (rocky, sand, clay). Most will readily rebloom if deadheaded. Some will bloom for months at a time.
Some salvias (Blue Hill, May Night) bloom for at least 4-5 weeks at a time. Their blooms are on spikes that can range from 4 inches to 12 inches tall. Once they're finished blooming, give the whole plant a heavy trim almost down to the ground, and within 3 weeks you'll be starting over with all new blooms again. These shrubby salvias are much hardier, surviving drought and heat without blinking an eye. They usually don't spread by seed.
Other salvias (Hot Lips, Wild Thing) bloom for 5-8 weeks at a time. Their blooms are on racemes and are usually quite long for the size of the plant (usually the same height as the plant or even taller). These salvias are usually a little more tender. Some are classified only as annuals, but they readily reseed if they are given good care.
Regardless of your zone or your moisture level, there is a salvia out there, just waiting to make itself a home with you.