Witch hazel is usually a large shrub, but it can grow into a small tree as it ages or when you prune it that way. So the honest answer to the witch hazel tree or shrub question is both. The plant itself does not pick a side. Its shape comes down to age, the species you have, and how much you cut away the lower growth over the years.
Look at two yards and you will see the split. In one, the plant reads as a wide, bushy mound with stems fanning out near the ground. In the next yard, the same kind of plant grows into a small open-crowned tree with a clear trunk you can walk under. Nothing is wrong with either one. They are the same species at different ages and under different care.
The reason sits in the plant's basic habit. Witch hazel grows as a multi-stemmed shrub by nature, sending up several woody stems from the base instead of one central trunk. Its branches are crooked and spreading, not straight and upright. Left alone, those low stems thicken and the plant stays wide and full. Remove them, and the upper branches keep climbing into a loose, tree-like crown.
Species matters too. Common witch hazel goes by the name Hamamelis virginiana. It is the native plant most people in eastern North America know. A few real numbers help you set your expectations before you plant. They tell you how big this plant gets and how much room it needs.
Most plants land in that middle range of 15 to 20 feet (4.6 to 6 m). Give it time and clear out the competing stems, and a strong specimen can stretch toward a tree form of 20 to 30 feet (6 to 9 m). Hold it as a bush and it tends to settle around 12 to 15 feet (3.7 to 4.6 m) and spread almost as wide as it is tall. Width often matches or beats height, which is why it can swallow a corner of a small yard fast.
Soil and light push the result one way or the other. A plant in rich, moist soil with room overhead reaches higher and looks more tree-like. One squeezed into a tight spot or dry ground stays low and dense. The plant adapts to what you give it, so the witch hazel shrub form and the small-tree habit are really two ends of one range, not two different plants.
The species you buy nudges this too. Common witch hazel leans tall and can carry a tree shape with some help. The Asian and hybrid types you see at garden centers often stay lower and wider, closer to a true bush. So check the tag before you decide which look you are after.
You get to steer this. To grow a tidy small tree, pick one to three of the strongest stems and remove the rest right at the base. Then limb it up by cutting off the low side branches over two or three winters, so a clean trunk shows. Pull any new suckers that pop up from the roots each year, or they will fill the base back in and undo your work.
Want the full bushy look instead? Then leave the lower stems alone and skip the limbing up. Just thin out dead or crossing wood now and then to let light reach the middle. A full base also screens a fence or hides a foundation better than a bare trunk does.
Start this work while the plant is young if you can. Shaping a three-year-old plant is easy, since the stems are thin and you can cut them with hand pruners. Reworking an old, thick clump into a tree is much harder and leaves big wounds. Either way, prune in late winter before the plant leafs out, and you will keep your witch hazel in the shape you want for years.
Read the full article: Witch Hazel Shrub: Grow, Care, and Bloom
