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We investigated the plasticity of seedlings to shade in six shrub species common in subtopical thicket, in order to assess their microhabitat preferences for regeneration. Cassine peragua and Sideroxylon inerme, which also occur in adjacent forests, were the most shade tolerant and would be unlikely to require canopy gaps for recruitment: their relative reduction in growth in dense shade was slight, as was their increase in leaf weight ratio (LWR); leaf inclination was adjusted to near horizontal in dense shade and maximum net photosynthetic rate (Amax) remained fairly low in sun-acclimated plants. Rhus glauca, which also occurs on forest margins, demonstrated the highest growth rates, especially in the open, and together with its high potential Amax is well-equipped as a pioneer, and would benefit from canopy gaps for establishment. Cassine aethiopica, which is also common in coastal forests, was slower growing than Rhus, but less shade tolerant than C. peragua and Sideroxylon and would probably benefit from canopy gaps for establishment. Pappea capensis and Schotia afra, which also occur in open savanna vegetation, demonstrated a growth and morphological pattern indicative of species adapted to periodic drought, in having a high ratio of woody conductive tissue to leaf tissue with accompanying slow growth. Their relatively poor performance in deep shade suggests that canopy gaps would benefit their recruitment. We concluded that canopy gaps may be essential for recruitment of the full species complement in sub-tropical thickets.