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:
Illicium anisatum 'Murasaki-no-sato'
Leucothoe axillaris 'Dodd's Variegated'
Magnolia yuyuanensis, Pick Up ONLY
Mahonia 'Beijing Beauty'
Osmanthus fragrans 'Tea Olive'
Pieris japonica 'Temple Bells'
Viburnum plicatum 'Summer Snowflake'
Zenobia pulverulenta 'Woodlander's Blue'