In forest communities, lianas proliferate through clonal growth. The diversity of clonal growth strategies and drivers of interspecific variation are largely unexplored. This study investigated the patterns of clonal proliferation in 11 temperate liana species in Japan, using stage-specific (pre- vs. post-climbing) comparison to capture the stage-dependent balance between vertical ascent and horizontal spread. We addressed the following three questions pertaining to lianas: (1) Does clonal growth produce preclimbing ramets on the forest floor? (2) Does clonal growth require attachment to a host tree (mechanical support for vertical ascent)?, and (3) Are life history traits, such as climbing type and maximum stem diameter, associated with interspecific variation in clonal growth? We genotyped 531 pre- and post-climbing ramets from 10 m × 10 m and 30 m × 30 m quadrats using microsatellite and single nucleotide polymorphism markers. We identified three distinct strategies for clonal proliferation as follows: two climb-prioritizing strategies (climb → creep and climb → switch trees) and one spread-prioritizing strategy (creep → climb). We detected preclimbing clonal ramets in 9/11 species, indicating a predominant mode of clonal proliferation in temperate forests. The host tree was essential for clonal growth in four species; other species proliferated clonally without the host tree. Trait-based analyses indicated that climbing type was as influential as species identity in shaping stage-dependent clonality. Our findings highlight interspecific diversity in the clonal growth strategies adopted by lianas as well as the ecological significance of life history traits in shaping clonal proliferation across forest strata.