Aquatic macrophytes are important components of any wetland ecosystem. How aquatic plants like cattail (Typha latifolia) grow and accrue carbon under the stress toxic oil sands process materials (OSPM) can exert is important information for the eventual remediation of the aquatic habitats affected by oil sands production. Leaf production and photosynthesis was measured in 96 transplanted cattail plants placed in 5 gallon plastic buckets containing four combinations of growing substrate: 1) pure consolidated tailings (CT) a by-product of the oil sands extraction process, 2) a soil / peat mixture atop CT (a potential remediation option), 3) the soil / peat mixture atop sterilized sand (a control for the potentially toxic constituents in CT), and 4) a pure soil / peat mixture. These four combinations were replicated four times in each of six constructed wetlands; each wetland was filled with either CT-affected water (another oil sands process by-product) or natural wetland water (three wetlands with natural and three wetlands with CT water). Production was estimated by measuring the length and width of every leaf and by tracking new growth by marking already measured leaves. We used a CO2 gas analyzer to measure photosynthesis (Licor 6400 Photosynthesis meter) of all plants. Preliminary results show that production of leaf biomass was significantly greater in those cattail that were unaffected by oil sands process materials. The rate of carbon accrual (photosynthesis) in cattail affected by OSPM was decreased, although a significant difference was not detected. The observed negative affect of OSPM on cattail suggests that the time needed for OSPM-affected wetlands to return to a natural, reclaimed state will be longer than observed in wetlands not affected by these materials.