Are your tree pests attracting wasps?

Wasps, often confused with bees, can cause issues on Colorado properties. They often sting without reason, can swarm on a property, and cause distress to homeowners.

One of the most common reasons that wasps may be gathering on your property is due to some pests that impact trees in the Evergreen, Colorado area.

In this article, we’ll go over:

  • The difference between bees and wasps and why it’s important to differentiate them
  • What attracts wasps to your property
  • The pests that may be responsible, and
  • What you can do

What is the difference between bees and wasps?

Bees are pollinators, spending their day looking for nectar or pollen from flowers. Wasps, on the other hand, are predators who hunt insects and will be attracted to your food. Bees will sting if they feel threatened, but wasps are more aggressive and may sting for seemingly no reason. Bees leave the stinger behind; wasps do not, which means that it have the ability to sting multiple times.

Bees are often covered with hair and have a fuzzy look, and their bodies tend to be rounder. Wasps have more of a thin, hourglass shape and have little or no hair and thus appear shiny. Bees have flat hind legs, while wasps have rounded hind legs.

From left to right: a honeybee, bumblebee, and leafcutter bee on various flowers and plants.

From left to right: a honeybee, bumblebee, and leafcutter bee on various flowers and plants.

Types of bees found in Colorado include honey bees (Apis mellifera), bumble bees (Bombus spp.), and leafcutter bees.

A Western yellow jacket (photo on left) and a hornet (photo on right), two of the most common wasps found in Colorado.

A Western yellow jacket (photo on left) and a hornet (photo on right), two of the most common wasps found in Colorado.

Yellow jackets and hornets are two of the more common types of wasps found in Colorado. The Western yellow jacket (Vespula pensylvanica) becomes particularly aggressive during the fall months due to their in-ground nests, which can house 200 individual wasps. They also tend to swarm around outdoor food (including pet food) and garbage sources.

According to the Colorado State Extension Service, Western yellow jackets are estimated to be the cause of at least 90 percent of the “bee stings” in the state.

The baldfaced hornet (Dolichovespula maculate) is a wasp found in Colorado that will build nests under overhangs, in trees, and in shrubs.

In most cases, you want to attract bees to your property but repel wasps. The easiest way to do this is to control the pests that serve as their food.

A honey bee covered in pollen on a flower in Evergreen, Colorado.

What attracts wasps and bees to your Colorado property?

Since wasps are predators, they are always looking for their next meal. If your tree is infested with any kind of pest, it means plenty of meals for wasps, which can cause them to swarm near your trees and around your property. They can be more aggressive when they are on the hunt, so they may be more likely to sting anyone nearby.

But if bees are attracted by pollen, why might they be near your trees?

If your tree has flowers that are blooming, the bees will be attracted to the pollen. This should not be a problem.

However, if your trees do not currently have flowers but you’re noticing a lot of bees, it could also point to a pest problem.

Some pests produce a sticky liquid called honeydew that can attract a variety of wildlife, including bees. While bees prefer pollen as their main source of food, if nectar availability is scarce, they will eat honeydew as an alternative despite its lack of needed protein.

Aphids cluster on aspen leaves on a Colorado tree.

What tree pests attract wasps to your Evergreen area property?

Wasps will eat a variety of insects, including tree insect pests.


Aphids, especially on aspens, are common pests that can attract wasps to your property. The aphids are considered their food source, plus the sweet and sticky honeydew that they create can attract wasps and bees.

In some circumstances, wasps can attack and even kill bees. Many types, including yellowjackets, consider bees as a source of food. This means that both the aphids and the bees attracted by the aphid’s honeydew become an incentive for wasps to invade your yard.

We have treatment options for aphids on your trees and plants, but you can also spray aphids off leaves with the jet setting on a garden hose (just be careful not to damage the leaves), or you can gently wash the leaves with some water and dish soap. You may have to repeat this method every few days, however, which is why we recommend our plant health care insect and disease control programs.

Learn more about aphids and how they can cause issues >>

Scale insects

There are around 8,000 species of scale insects, many of which can be found in the Colorado Front Range region. They can be particularly damaging on conifers but can impact deciduous trees as well.

Wasps see scale insects as an ongoing food source, so they will be more likely to keep coming back to your property for a scale insect meal as long as the insects continue to infest your trees.

Read about oystershell scale, pine needle scale, and striped pine needle scale >>

Ponderosa pests

Ponderosa pines have several pests that can attract wasps, including grey powdery pine needle aphids (Eulachnus spp) and striped pine scale (Toumeyella pini).

Just as with other tree pest issues, treating the source of the problem (the pest infestation on your trees) will dissuade wasps from gathering on your property.

Learn more about Ponderosa pines and the pests and issues they may encounter >> 

A bumblebee gets pollen from a tree blossoms in Evergreen, Colorado.

What Should You Do if you Notice Wasps on Your Property?

First, ensure that they are wasps, not bees. Bees are beneficial for your plants and trees and provide needed pollination to help your plants grow and spread. Flowers, especially, have a beneficial relationship with bees.

Once you’ve determined that the flying yellow-and-black insects are wasps rather than bees:

  • remove any outdoor food (including pet food),
  • make sure your trash is covered well
  • consider removing any hummingbird food from feeders
  • refrain from wearing heavily scented perfumes or scents when out of doors

Most importantly, contact the professionals at LAM Tree Service for an inspection of your trees. Many of the pests that attract wasps are miniscule and may be missed.

Spraying or trapping doesn’t work to rid your property of wasps because the pests will just attract other wasps. Instead, treating or preventing the insect pests will prevent wasps from finding and returning to your property.

Harming or trapping bees is also not a solution to the problem because bees are beneficial to your landscape, and you want to encourage them and other pollinators to visit your property.

A wasp nest in a conifer tree in Evergreen, Colorado.

Keeping Your Trees Healthy

If trees aren’t receiving proper nutrients or water or are improperly pruned or damaged, they become stressed.

Stressed trees are more likely to suffer from a pest issue or disease.

Trees infested with pests attract wasps.

Tree care issues are often related, as in the example above, which is why we emphasize keeping your trees well cared for and maintained.

If you have any questions about the health or care of the trees on your property, don’t hesitate to contact the tree professionals at LAM Tree Service to request an inspection of your trees or more information about our Plant Health Care services.

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