Dwarf carnation (`Monarch Yellow' and `Monarch Purple') was germinated and grown at 20 °C for 3 weeks. Following transplant (21 d from seeding), seedlings were grown at 16 °C and either 9 or 16 hr daylength. Irradiance was adjusted to 10 mol/m2 per day. Growth and development in response to photoperiod was significantly different for the two cultivars in the `Monarch' series. Flowering at long days was faster with 118 d from seeding for `Monarch Yellow' and 128 d for `Monarch Purple'. Under short days, flowering was observed 128 d from seeding in `Monarch Yellow' and 144 d for `Monarch Purple'. Ten days with short photoperiod initiated at transplant followed by long days resulted in more branching without significantly delayed development for `Monarch Yellow'. No effect on branching or rate of development was observed in `Monarch Purple' with 10 initial short days compared to long days throughout.