Chromosome doubling by colchicine treatment, and the morphological characteristics of tetraploids and their inheritance were investigated in Salvia. Colchicine treatment of seeds had little effect on germination, but adversely affected true leaf development and the survival rate of seedlings. A 50% reduction in true leaf development was observed at 500 ppm colchicine in S. coccinea ‘Coral Nymph’, at 250 ppm in ‘Lady in Red’ and at 750 ppm in S. patens ‘Blue Angel’. Of 50 seeds of S. coccinea ‘Coral Nymph’ treated with 500 ppm colchicine, 12 seedlings survived, of which five individuals were confirmed to be tetraploid, including two presumed chimeric polyploids. The tetraploid plants had larger, thicker leaves and enlarged inflorescences and flowers compared with diploid plants, which increased their ornamental value. Most of the tetraploid plants produced viable pollen and self-pollinated seeds were obtained from four tetraploid individuals. The 18 second-generation seedlings were confirmed to be tetraploids and their flower and leaf morphologies were identical to those of the tetraploid parents.