Tree vs Shrub

What's the difference between a tree and a shrub? Is there an actual technical difference between trees and shrubs? I get this question fairly often.

The answer is - nothing but a random guess about its height. If a pine tree is 30 feet tall and you can barely see its top, you call it a tree. If a plant with green leaves and a woody trunk is 2 feet tall and sitting at the side of your driveway, you all it a shrub. It could easily be that if you waited twenty years that your driveway-side shrub will turn into a tree. It could also just sit there in a shrub like size forever.

A small shrubby shaped plant could remain a shrub size because that's what nature intended. That plant could also remain a shrub size because there wasn't enough light for it to grow to a taller height. Maybe, if it had more light and fertilizer, it would have turned into a tree at some point.

There are of course some common sense types of exceptions to this rule. If you see a baby oak tree -

baby oak tree

You probably wouldn't call that a shrub. You would call it a young oak tree. However, that means you have to KNOW it will grow up into a larger tree. I know several people who call this little plant a shrub :) On one hand, you could say it's not a shrub or a fern, it's a little oak tree. On the other hand, by the definition given above, you COULD call it a shrub and be quite accurate. Right now it's a little woody plant. In a few years, when it's huge, it probably wouldn't count as a shrub any more in anybody's imagination.

So to summarize, don't worry too much about what you call a particular green thing that you see. You can call it a tree or a bush or a shrub. A better aim is to figure out what KIND of a plant it is, to learn more about the world around you!

Note: I find it quite funny that some people land on a page that is about Tree vs Shrub and think it's some sort of an epic battle, where the Trees (maybe the ents?) take on the smaller but oh so feisty shrubs :) Some people think Shrub vs Tree is a "which is better" argument. Is your lawn more aesthetically appealing if it has majestic trees swaying in the wind, or cute little shrubs that birds can nest in? Maybe those can be the subject for future articles ...

Trees of Sutton Massachusetts

Massachusetts Foliage Photo Collection
Sutton Massachusetts Photo Album