The same plant gets sold as a shrub in one catalog and a small tree in the next one. The shrub vs tree difference is not a matter of taste, though. A shrub is a multistem woody plant that stays under 16 feet (4.9 m) tall, and a tree runs taller on one trunk. What is a shrub in the yard, then? Count the woody stems at ground level and check the mature height on the tag. Virginia Cooperative Extension draws the line right at that 16 foot mark.
Stem count does most of the work here. A tree pours its growth into a single trunk that thickens each year and carries the leaves overhead. A shrub sends up several woody stems straight from the base, and every stem holds part of the crown. You end up with a plant that is wide and leafy near the ground, which is why a row of shrubs hides a fence and a row of trees never quite does.
Pruning blurs the line fast. Strip the lower stems off a large shrub, keep one leader, and in two seasons you have the outline of a small tree. Telling a large shrub from a small tree is partly a matter of interpretation and pruning. Two nurseries can file the same species in different sections and both be right about it. Size control still sits low on the list of good reasons to prune, because pruning is no substitute for picking the right plant. Anything that wants twice the room you have will fight you every single year.
Those classes matter more than the word printed on the tag. A large shrub crowds a foundation bed that a small one would have suited, and the mistake shows up three years later when the window is gone. Common witch hazel sits right at the top edge of the whole question. It runs 15 to 30 feet (4.6 to 9.1 m) tall, above the shrub cap, so a mature plant reads as a small tree even though most lists file it with the shrubs.
Bush vs shrub trips people up in the shop, and the honest answer is that gardeners use both words for the same plant. Bush sounds casual and shrub sounds formal, but no height rule or stem rule separates the two. Nurseries and plant tags swap between them with nothing behind the choice. Read the mature size on the label and let the wording go.
Pull the low branches aside and count the woody stems where they leave the soil. More than one from the base, on a plant that matures under 16 feet (4.9 m), means you are looking at a shrub, whatever the tag calls it.
Name the size class before you shop, not after you get home. The class decides which plants can go in that bed at all, and it stops you putting a 9 foot shrub under a low window. Measure the gap you need to fill, write the number down, and shop only inside that class.
Shrubs work as the walls, ceilings and floors of a yard, and they build the outdoor rooms you move through. A tree gives you the roof over all of it. Get the stem count and the mature height right at the nursery, and you will not be fixing that choice with a saw in five years.
Read the full article: 10 Flowering Bushes and How to Pick One
