This study presents the first observations of early-season colony development of Ropalidia plebeiana in Canberra, Australia. The growth pattern of three R. plebeiana nests was measured during weekly observations from October 2006 to January 2007 and showed that nests steadily increase in size over the early summer to approximately 50 cells when the nest is newly established and to approximately 170 cells when nests from the previous season are re-used. A first generation of adult females is produced by December, and the bimodality of the curves of egg, larval and pupal numbers indicates that these three developmental stages last approximately 2-3 weeks each. The nesting cycle of R. plebeiana in Canberra commences approximately 2 weeks later than in coastal Australia, the shorter summers in this inland region restricting the length of the active season. R. plebeiana did not form dense nesting aggregations in Canberra as described elsewhere, with only small colonies consisting of a single or just a few nests. Characteristic comb-cutting behavior of the species was observed but this did not result in complete nest division as recorded from coastal populations.