What Is Witches’ Broom and What Causes It?

Unique twists and odd growths aren’t uncommon on our backyard trees, and you might even say it gives them character. But if you’ve ever stared at your tree and wondered why that strange nest-like structure looks so deformed, keep in mind that it might not be a bird’s nest at all!

Witches’ broom is a fairly common tree deformity, and despite its name, witches’ spells have nothing to do with its growth. If you’re curious about this odd mutation in the trees around your home, here’s what you should know.

What Is Witches’ Broom?

Witches’ broom looks like a mass of twigs growing from a central point on a tree. It can appear as a large bunch of branches, or a smaller ball-shaped cluster of twigs or needles. Often, the resulting bundle looks like this condition’s namesake: a witch’s broom.

Witches’ broom can happen on both coniferous and deciduous species. It can also happen on certain vines, shrubs, and perennial plants. Some trees are more likely to contract witches’ broom than others.

Though witches’ broom is unsightly, it isn’t always fatal. Odd-looking growths won’t hurt the tree, but they may be a sign of underlying tree diseases worth treating.

witches broom

What Causes Witches’ Broom?

Witches’ broom is often a stress response from a suffering tree. In the same way, your body might cough or sneeze when fighting a virus, witches’ broom is sometimes a response to an infection. There are a few possible underlying causes when it comes to this strange condition.

First, is a parasitic bacteria called phytoplasma, which can interrupt the flow of sap and nutrients. Insects like mites and aphids, which also sometimes carry pathogens, can stress the host tree as well.

When doing a visual inspection, you should also be on the lookout for powdery mildew and other funguses. Parasitic plants like dwarf mistletoe can also be a culprit, though their shoots may be hard to spot without cutting the witches’ broom for a closer inspection.

Last, but not least, witches’ broom can sometimes happen without an underlying condition at all, simply as a genetic mutation.

How Do You Get Rid of Witches’ Broom?

As you might guess, getting rid of witches’ broom is easy: all you’ll need to do is prune any branches with growths you don’t like.

However, unless you treat any underlying tree problems, the witches’ broom may return over and over every few years. Inspecting your tree for pests and other problems is always a good idea if you’ve noticed these disfiguring growths. In some cases, tree removal may be the only option, especially if the infection or disease is likely to spread to nearby trees.

If you aren’t sure whether your witches’ broom is a symptom of a disease or simply a strange growth on a healthy tree, working with a plant specialist is a good idea.

Contact the Yard Care Specialists

Wondering what’s going on with your tree? If pests are causing your witches’ broom, our team can help.

Our pest control services can identify your infestation and provide a quick and effective response—no matter how large the problem is. Get in touch today to learn more.