What Are the Balls on Oak Trees?

People tend to love their oak trees, but when there are weird looking balls growing on the leaves of the tree, what exactly does this mean? And how can oak tree owners get rid of them?

These small brown balls hanging from your oak tree are called oak galls, also called oak apples. They are caused by non-stinging wasps that come onto the branches or leaves of the tree and lay their eggs there. They look unsightly, but they can also harm or even kill the tree in some instances. Thankfully, they are also very simple to get rid of.

Also Read: How Do Oak Trees Reproduce?

What Are Oak Galls?

Oak galls are brown balls found on oak trees on or near the branches, twigs, leaves, and even the flowers of the tree. When these wasps lay their eggs there, they inject a hormone into the plant tissue that makes it grow abnormally.

In addition to abnormal growth, the affected tissue will surround the developing wasp larvae. The condition isn’t normally serious; however, if infestation becomes too severe, it can be fatal to the tree.

Yay galls

For this and many other reasons, most owners attempt to get rid of these galls before they spread and become too prevalent. Don’t worry, though, because getting rid of galls is a lot easier than it might sound.

Oak galls / oak apples usually resemble a large seed pod or even a growth that resembles a tumor. They are usually formed in early spring and are typically found at a bud break.

What to Do About Oak Galls

The first thing you need to do is make sure that you find the galls and not any other type of growth that may be on your tree. You don’t want to remove anything that is supposed to be there.

You should also look for any of the symptoms of galls, which include:

  • Scorched or blackened leaves
  • Curled leaves
  • Leaves that fall off prematurely
  • A solid mass that encircles an entire branch or two

Next, you’ll want to take some pruning shears and get rid of all of the branches that have galls on them. Once the branches are on the ground, step on the galls so that any developing larvae are destroyed. You can also burn the galls.

When you’re done, take all of the oak galls and place them in a resealable sandwich or garbage bag. Then throw them in the trash. Once this step is complete, you’ll need to thoroughly rake the entire area so that all of the galls are removed.

Why do you have to rake the area? Because the insects that produce these galls will bury themselves in the debris and stay there throughout the winter. And to keep these insects from coming back, you can:

  • Hang some bird feeders on the tree. Birds are natural predators of gall-producing wasps.
  • Apply carbaryl to the branches in the spring when the buds break. When you do this, it stops the females from laying their eggs there in the future.

If you apply carbaryl, make sure that you pay close attention to the instructions on the package because each brand is a little bit different.

Can it Be Something Other Than Galls?

When you see round balls on your oak tree, it is usually galls, but this isn’t always the case. They could be oak leaf blisters and not galls. Oak leaf blisters have the following characteristics:

  • Pale green or orange color, then turning brown or black
  • Appear as raised spots on the leaves
  • Are slightly indented or sunken underneath

If you remember that galls are round and blisters are usually sunken underneath, you should be able to tell the difference between the two. If you aren’t sure, you can seek the help of a professional.

Oak Galls
Pxhere Oak Galls

Which Insects Create Oak Galls?

Galls are usually a result of the non-stinging wasps, which are very tiny. There are, however, other life forms that produce the same results, and they include:

  • Bacteria
  • Fungi
  • Mites
  • Nematodes
  • Other insects

Some people recommend just leaving the galls on the tree but at the very least, galls can distort the leaves, cause the leaves and tree to have an ugly appearance, and even cause the leaves to drop too early.

Therefore, most experts recommend that you go ahead and remove them, especially because they can overpower the tree and cause it to have more galls than you like to see. This can happen quickly.