Blog - Lawn Buddies

Do My Trees and Shrubs Need Insect Control in Winter?

Written by Chase Coates | Dec 01, 2022

You’d think bugs would be exhausted by winter time, right?

All that chewing and reproducing. All that effort spent munching your tree bark, nibbling your arborvitae, burrowing and gnawing.

It makes your teeth hurt just thinking about it.

Are they still at it out there in the winter, wearing little bug boots and mittens?

Do trees and shrubs need insect control in winter?

Let’s find out.

Even Bugs Need a Break

The good news: most bugs aren't actively feeding on your trees and shrubs during Idaho winters.

They’re curled up under the bark, or hiding in cozy places, maybe sipping cocoa and watching Netflix, waiting for it to warm up so they can chow down again.

You can relax, too — applying pest control for trees and shrubs in winter would be a waste.


Here in cold Idaho, the pesticides sprayed on leaves would just freeze to your plants.

Systemic insecticides don’t work in winter months here, either. Those tree injections that work by moving the chemicals through your tree’s vascular system can’t do their job because your trees are dormant. They’re not moving anything. The treatment would just sit on top of the frozen ground.

Here in Idaho, our last tree insecticide treatment is done in September if applied to the leaves. Our last systemic treatments, done by injection, happen in October. That’s your last chance to protect trees and shrubs from winter pests with spray or injections.

Pest Control for Trees and Shrubs in Winter: Dormant Oil

If you’re the worrying type and stressed that damaging insects and their hungry larvae are waiting to pounce on your trees and shrubs at the first thaw, you can treat them with dormant oil in early spring.

Also called horticultural oil, dormant oil spray is a highly refined petroleum product used as an insecticide to suffocate insects and insect eggs that have overwintered on trees and shrubs.


Instead of poisoning the bugs, you’re basically smothering them with the oil. The oil kills any lingering insects as well as their eggs, so they won’t hatch in the spring.

Lawn Buddies technicians will apply the oil spray in early spring while your trees and shrubs are still dormant.

Then, bye bugs. It’s a great way to protect trees and shrubs from winter pests waiting to pounce in spring.

Are Your Trees and Shrubs Ready for a New Best Friend?

Do trees and shrubs need insect control in winter? Rest easy this winter and set at least one stress aside— bugs are taking the winter off.

But spring isn’t that far away.

Expert plant health care like tree injections, deep root fertilization, and dormant oil treatments are available for our Idaho Falls and Boise customers who use our full-service lawn care program.

Choose an Idaho Falls or Boise professional lawn care service that bundles your yard’s most-needed treatments into one convenient, no-fuss plan.

Fertilizing, weed control, grub control. Done. Tree health care? Double done.

We’ve got your back.

Got a few minutes? That’s all you need to get started.

Fill out the form on this page.
Call us at (208) 656-913.
Or read more about our services.

Then kick back and relax in your healthy, thriving yard.