Tag Archives: tree shoots

About Tipping

No, not that kind of tipping.

I’m talking about snipping off the ends of tree branches to shorten them.

In the drawing, the blue line indicates roughly where someone snipped off the ends of branches a, b, c, and d. You can see how the tree responded: a spray of profuse new growth (“shoots” or “water sprouts”) from near the ends of the tipped branches.

Why?

At the tip of a tree branch there is a so-called terminal or apical bud. This specialized bud regulates growth of the entire branch. (After all, the tree needs to grow up and out to reach that all-important sunlight!)

A hormone is involved, called auxin. Think of auxin as being like a sleep potion. All those many other buds lying under the bark along each branch? Auxin keeps those buds dormant.

But if I snip off the terminal bud, some of those dormant buds along the branch “wake up.” They send out shoots which will become twigs which will become new branches.

Tipping a branch to clear a sidewalk or street is usually counterproductive. Within a year or two, the problem will be twice or three times as bad. Look how many sprouts were growing on this tipped Bradford pear. (Located on Austin Avenue at its intersection with Euclid. Thanks to Meghan for identifying this hazard to pedestrians.)

Instead, always cut a branch just beyond a node. A node is simply where a leaf, twig, or secondary branch attaches to a larger part of the tree.

Put differently, your goal is always to leave a bud which can become the new terminal or apical bud of that branch, controlling that essential hormone auxin, so that the tree can grow up and out.

Repair work: