A Canadian selection from T. x flavescens that grows vigorously when young but less so when older. Develops a uniform, round crown with a perfectly straight trunk and ascending branches. It reaches a height of 18 - 25 m and a width of up to approx. 15 m. The glossy, dark green leaves are bare underneath and remain a nice green until late in the summer and remain on the tree long into the autumn. The leaf edge has rough lobes. Profuse flowering begins in late June. The hybrid T. x flavescens is very probably a cross between T. cordata and T. americana and is not cultivated hardly anywhere anymore. 'Glenleven' is a cultivar that came onto the market in Europe fairly recently and with which there has been little experience as of yet. Highly resistant to the heat of an urban environment.