To be frank, T.princeps as the only blue trachycarpus have white powder not only present on the backsides of leaves, but also at the upper leaf surface and petioles. So they can be a green palm looked from above, and blue or silver from below , what is fascinating is that they can be a blue or even white palm from above and snow white from below other trachycarpus can not beat.
Here are some photos demonstrating how white the upper leaf surface as well as the lowerside could be .
Is your princeps like this




