Recent research on complexity development has demonstrated the need to distinguish between specific types of subordinate clauses and consider L1 influence and individual variation. The present study combines these factors and makes finer distinctions between clause types than usual in complexity research. A case study following five Norwegian learners of English over four years shows that individual clause types have different developmental trajectories and that learners may develop in syntactic diversity even when showing little change in amount of subordination. A lack of specific clause types in the L1 can lead to late development of these in the L2, and higher uses of subordination in particular areas may boost complexity in the L2. Individual differences were found mainly in pace.