Leaf anatomical and physiological traits influence rates of individual plant and ecosystem function. Although leaf trait variation among different species can be largely attributed to broad climatic gradients, variation at finer spatial scales and within species is less known for many habitats and taxa. Pine barrens are particularly understudied despite regional and ecological significance in northeastern North America. We assessed variation in specific leaf area (SLA), leaf dry matter content (LDMC) and leaf thickness (Lth) for three dominant understory shrub species in the New Jersey Pine Barrens. We hypothesized that traits would vary among and within species along an environmental gradient from upland forest to lowland bog. We further hypothesized that SLA would be larger and LDMC and Lth would be smaller in the upland forest than in the wetter, more nutrient-poor bog, reflective of stress tolerant plant strategies. Unexpectedly, all three species had smaller SLA and larger Lth in the forest than in the bog. LDMC was larger in the forest for Black Huckleberry (Gaylussacia baccata) and Sweetgale (Myrica gale) but smaller in the forest for Lowbush Blueberry (Vaccinium angustifolium). A trade-off between SLA and Lth appears constrained and potentially adaptive in multiple ecological contexts. However, trait-trait correlations involving LDMC were inconsistent across scales. These shrub species may be responding in similar ways to dominant environmental variables in the bog, while multiple environmental variables in the forest may promote species-specific responses and divergent trait correlations. Differences in light and water availability may be influencing leaf trait variation more than soil nutrient availability, while soil pH may be an additional driver of variation in leaf functional traits for these understory temperate shrubs.