A. There are several differences between the two. A shrub usually has woody stems that are smaller than 2ft in height, within which there is an apparent main trunk or several main branches. Shrubs are often multi-stemmed but less dense, whereas bushes are very dense with no apparent stem or trunk. Some people distinguish that shrubs are actively growing to fewer than 6ft, whereas bushes are taller with an undefined trunk. A small tree can be considered a large shrub or a small tree can be considered a small bush, but there is no specific dividing line between the two.