The line between whether a plant is a "tree" or a "shrub" is sometimes very thin and quite blurry! We use the following criteria to decide which type applies to a certain plant:
Rhododendron x 'Touch of Pink'
Serissa japonica 'Bumblebee Delight'
Stachyurus praecox 'Sterling Silver'
Zenobia pulverulenta 'Woodlander's Blue'