Rhododendrons as trees
I have often recommended rhododendrons when gardeners along the northern coast are looking for small evergreen trees with showy flowers. The usual response is something along the lines of, "no, I want a tree, not a shrub."
There is no firm botanical distinction between a large shrub and a small tree. It often comes down to how the plant is shaped by the gardener. Since they are in bloom now, I'll take this opportunity to illustrate the principle with a photo from a local subdivision where rhododendron trees are found throughout. A canopy of magenta projects above the rooftops and can be seen from two blocks away.