From the moment they sprout in spring to the final drop in fall, leaves on our trees captivate us.

That’s why anytime leaves don’t look their best, we want to spring into action and help.

Our blog reader, Gwen, recently asked, “I believe insects have burrowed into the leaves of my burr oak tree, now they’re dying and turning orange. Is there a cure?”

If you also see bumpy, blistered oak leaves with a funky color, read on to learn why this is happening and what you can do.

Why You See Bumps or Round Balls on Oak Tree Leaves

Oak leaf blister disease and oak leaf gall are the top two culprits when it comes to problems with oak tree leaves. There are a few ways to tell them apart.

Oak Leaf Blister Symptoms

Trees suffering from oak leaf blister will develop raised spots scattered on the leaves. Underneath, leaves will feel slightly sunken or indented. That’s what was plaguing Gwen’s oak trees!

The blisters are first a pale green or orange and then eventually turn brown or black. Severely infected leaves will curl or drop early.

Galls on Oak Leaves

Galls are abnormal growths that crop up on trees after insects or mites settled in. They’re clusters of brown or orange balls that vary in size and cover tree leaves and branches.

Depending on the what insect is causing it, some galls are hairy while others are perfectly round and smooth.

What to Do About Bumps on Oak Leaves

Good news and bad news. Oak leaf blister and oak leaf gall cause little harm to trees. But both are ugly to look at–especially on your once-beautiful oak tree!

Luckily, infected trees typically bounce back with proper plant health care. Most of the time there’s no need for a chemical treatment.

If your tree has oak leaf blister:

If your tree has oak leaf gall:

  • When galls are in their early stage in spring, prune infected twigs.
  • Rake and dispose of fallen leaves in autumn. This may help get rid of resting insects and mites that brought on the infestation.

If you suspect your tree needs extra attention, have your arborist see your oak tree in person!

Related Blog Posts

Oak Tree Fall Foliage
Tree Selection Guide

Best Oak Trees To Plant for Color

Here are some common oak tree varieties that can give you an amazing tree for shade, great texture and interest, and amazing fall color.
Read More
1501041 Oak Wilt
Leaf & Needle Problems

Why Are My Oak Tree Leaves Turning Brown?

Is my oak tree dying? Is this oak wilt? The key to diagnosing your browning oak tree is looking past the color and checking for other signs and symptoms.
Read More

Sign Up For Free Tree & Landscaping Tips! 

Subscribe to the "The Sapling," the Davey Blog's email newsletter, for the latest tips to keep your outdoor space in tip-top shape throughout the year.

Plus, receive a free instant download of our landscape seasonal checklists when you sign up!

Get In Touch With Us!

We pride ourselves at Davey Tree on providing prompt, professional and personalized service from certified arborists that live, work and engage in your community. Contact one of our Davey Tree specialists for your residential, commercial, utility, or environmental needs.

Let's Find What
You're Looking For!

Davey uses cookies to make your experience a great one by providing us analytics so we can offer you the most relevant content. By continuing to use this site, you accept our use of cookies. View our Privacy Policy for more information.