What the heck is turning your plants into lace-y skeletons?
If it’s late June, July or August in the Front Range of Colorado, Japanese beetles may be to blame.
“What do Japanese beetles look like?” you may be wondering.
Japanese beetles are metallic green insects with dark orange wings, making their backs look metallic orange. They have white spots along their sides.
And they will eat their way through your yard with reckless abandon.
Japanese beetles are spreading along the Front Range of Colorado, including the metro Denver area and parts of Pueblo.
So, what can you do about Japanese beetles?
It’s 100% normal to go out and buy the first products you see to get rid of Japanese beetles.
But, while these products may be well intentioned, many have not proven to be effective in reducing damage on your plants. You may be throwing away good money.
And some products are very toxic to the good insects in your garden, like bees. You may be unintentionally nuking your own garden.
In this video about Japanese beetles, you’ll get:
- A basic introduction to Japanese beetles, so you know what to expect
- 2 primary ways to think about Japanese beetle control, so you use your time well
- A look at some of the plants they REALLY like
- Myths about ways to get rid of Japanese beetles, so you don’t waste your money on products that don’t work
- A more detailed resource, if you want it, that includes Japanese beetle control products on the market
Prefer to read?
Scroll down for the transcript.
I’ve also included helpful resources at the end of this article, including different products you can use to control the beetles.
Transcript of Japanese beetle video:
Japanese beetles in Colorado.
They’re working their way up and down the Front Range.
These beetles can be a royal pain in the bootie for your flowerpots, your garden, your trees and even your lawn.
So, in this video, you’re going to find out what you should know about Japanese beetles in Colorado and how to control them.
Hi, I’m Ann with Go West Gardener.
Inspiring new western gardeners to find their green thumbs with flowers.
Real quick, in addition to my 15 years of hands-on experience with gardening in Colorado, I’ve completed more than 120 hours of formal training in western gardening, and I continue to take courses and workshops, so I can help you with topics like the one today: Japanese beetles in Colorado.
Unfortunately, Japanese beetles are here to stay along the Front Range. So, it’s helpful to plan ahead and know what your options are.
In this video, I want to give you:
- A basic introduction to Japanese beetles because there’s A LOT of misinformation out there.
- I’m going to share 2 primary ways to think about Japanese beetle control.
- I’m going to debunk some myths about ways to get rid of Japanese beetles. (And yes, you will see your neighbors doing these things.)
- And I’m going to point you to a more detailed resource, if you want it.
Let’s jump in.
Japanese beetles go through a one-year life cycle, but if you have a yard you care about, the real “joy” with beetles comes in the second half of the summer in Colorado.
Around the very end of June or early in July, the adult beetles will emerge from your lawn and start showing up on your plants.
And now they’re ready to eat their way through your garden in July, August and sometimes early September.
Japanese beetles have two priorities:
- To eat and
- To reproduce
If you had them last year, you know they will chew their way through your plants, creating holes in your plants and turning them into lacey skeletons.
Depending on the plant, they may eat the flower petals, they may eat the leaves, or they may eat both.
And between their dinner parties on your plants, the females will fly down to your lawn, dig a few inches down to lay eggs, and then come back up and start the process all over again.
So now, you don’t just have the adult beetles to think about, you have their babies too.
As the eggs hatch, the larvae — which are these little white grubs — will feed on the roots of the grass in your lawn.
And they’re especially fond of lawns that we have along the Front Range of Colorado, like Kentucky bluegrass, fescue and ryegrass lawns.
So, picture this…
You’ve got the adult beetles chewing on your plants above ground, and you’ve got their babies — these little white grubs — chewing on the roots of your lawn.
Not a good time!
As temperatures drop, the grubs will dig deeper into your soil for the winter and then come up closer to the surface again in the spring before they emerge as adult beetles in late June and early July.
So, if we’re going to talk about how to control Japanese beetles in Colorado, it helps to think of them as affecting your yard in two ways:
- You’ve got the adults eating your plants, and
- You’ve got the grubs chewing on the roots of your lawn
From a control and treatment perspective, you can deal with the adults, and you can deal with the grubs.
Let’s talk about how to control the adults that are eating your plants.
One of the biggest things you can do to PREVENT damage is avoid planting flowers and trees that Japanese beetles love in Colorado.
These are plants like roses, Virginia creeper (it’s a vine you’ll see growing along fences), linden trees and some types of fruit trees.
I had a plum tree that the beetles would just fall out of and land in your hair, like the tree was dripping with insects.
It was so gross.
And that’s just the start of what they like to eat.
Every year I feel like I find them on something new.
But let’s say you absolutely love a plant, like roses, and you want to plant them.
Then just know that your roses will look great early in the summer, the beetles will try to chew them up in the middle of the summer, and then, it’s possible your roses may give you flowers again in the early fall after the adult beetles have died.
Now, you may be thinking, so prevention is great, Ann, but I have beetles NOW.
“What can I do about them?”
“How do I get rid of them?”
“Can’t I just spray them?”
Yes, there are insecticides and some bio-controls you can use to kill Japanese beetles.
But do your research because many of these also have a negative effect on bees and other pollinators — the really good insects in your garden that we need.
Later in this video, I’m going to share a resource where you can find a list of product options for you on what you can apply to your plants, including how toxic they are.
If you DO have beetles and you DON’T want to use poisons, one of the most effective things you can do is to put on a pair of garden gloves, put together a container of soapy water, and then knock or pick and drop the beetles into the soapy water to drown them.
(This works with small amounts of beetles.)
Dig through your recycling bin to find a container you can use.
I will often save an empty, plastic butter container that I fill up with soapy water.
I plop the beetles in and then put the top on until I know they’re dead.
Once the beetles are dead, you can throw them out in your trash, you can compost them, you can even bury them — they won’t cause any harm at that point.
When the beetles are chewing on your plants, your plants are releasing a compound that’s like a magnet to more beetles.
For me, this always makes me think of the local ice cream truck.
On summer nights, it comes cruising through our neighborhood, playing that distinctive musical jingle, and the kids come running to it.
So, your plants are basically doing the same thing as that ice cream truck playing that song, and the beetles don’t want to miss it.
Here’s what this means.
It’s better to get the beetles early before you have a feeding frenzy on your hands.
If your plants haven’t been damaged too much yet, it’s like the ice cream song is really quiet. But if you wait until your plants have a lot of damage — the music will be blaring and more beetles will come.
Beetles are groggiest at cooler times of the day and when it’s darker, like in the evening or early in the morning, so those are the best times to try to pick them off your plants.
If you try catching them during the day when it’s warm, they’ll quickly fly away. I have to say, this doesn’t stop me from trying to catch them, but I often miss many of them.
Okay, so that’s one option.
You can pick off the beetles by hand.
But let’s say you have A LOT of beetles, like on your roses or on your vines.
I recently took a Colorado gardening course where the speaker was talking about using a shop vac to vacuum up the beetles from the vine that the beetles were eating.
I have not tried this, but it sounds interesting if you have too many beetles to pick off.
And you know what I’m talking about when you have 5 beetles the first day, and then 20 the next day, and then 172 the next day.
The beetle party can get out of control quickly!
You’ll still need to kill the beetles when they end up in your shop vac, and you’ll need to find a way to keep them from clogging up your filter.
But I’m passing this idea long in case it inspires you.
If you see beetles on the ground, you can squish them.
A few years ago, there was some question about whether this would attract more beetles to your home, but that’s no longer considered to be an issue.
What the beetles are attracted to is your plants because they’re playing that ice cream truck song.
If you happen to have chickens, you can let your feathered friends help you with pest control.
And the last thing I’m going to mention is that one of our state universities and one of our state agencies are running tests on ways to control the beetles, including releasing other insects that will attack the beetles.
So, fingers crossed we’ll have more options in the future.
Okay, so let’s pause for a moment and talk about one thing that has NOT proven to be as effective for protecting your plants.
You may see your neighbors hanging up bags to catch the beetles — Japanese beetle traps.
And I get it, it’s an appealing solution.
Here’s the thing.
These bags will definitely catch beetles, and they’re great if you’re part of research project on how many beetles are present in your area.
However, they have not shown to lower damage to the plants in your yard.
In fact, you could actually end up increasing the damage.
The reason is these bags are a magnet for beetles to your yard, and the bags don’t catch every beetle.
So you’re basically ringing a dinner bell for the beetles to come home.
Save your money and skip the bag.
Also, you may go on the Internet and read about remedies with different types of oils, including neem oil and garlic.
My understanding is, in the trials that have been done with Japanese beetles in Colorado, these remedies have not shown to be effective.
Okay, so we’ve talked about the big controls you can use for the beetles eating your plants.
But remember, you’ve got the adult beetles on your plants, and their babies are eating your lawn.
Let’s change gears and talk about how you can protect your lawn.
But first, I want to make sure I’m clear.
When you are protecting your lawn, you are NOT going to prevent Japanese beetles from showing up on your plants.
The beetles can fly, and you will still end up with beetles from all your neighbors’ lawns.
The point of treating your lawn is to keep your grass alive.
What happens is the grubs eat the roots of your grass, particularly in August and September, so your grass has trouble absorbing the water it needs to stay alive.
And here in Colorado, this is the time of the year when our grass is already kind of stressed out from the heat, right?
You also may end up with critters, like raccoons, digging holes in your grass trying to get the grubs.
So, here are some options for protecting your lawn.
If you are moving into a new home and you have a choice of grass, the beetles are less crazy about some “warm season” grasses, like Bermuda, Blue Grama and Dog Tuff grass.
So, you may want to do some research on what it’s like to have a warm season grass lawn.
Or, you may want to skip a grass lawn all together.
If you have a traditional lawn, like Kentucky bluegrass, you can keep your grass healthier starting in the spring.
This makes it more resistant to beetle damage.
This means mowing your grass at a longer length (not short like a putting green).
Longer grass means you have longer roots. Shorter grass means shorter roots, and shorter roots are vulnerable.
It helps to fertilize your lawn, so it gets the nutrients it needs.
It helps to “aerate” your lawn — that’s when the dirt plugs are taken out of your grass — so air and water can get down to the roots.
And it helps to give your lawn a deep, soaking water and then no water for the next few days, rather than watering for a short amount of time every day.
All of these steps will keep your roots happier.
And the healthier your grass is going into July, August and September when those grubs are chomping away, the more your lawn will be able to handle the damage from grubs.
Here’s another thing.
Female beetles like damp yards to lay their eggs, so if your lawn is healthy and you can minimize your watering in July and August, you will deter the beetles from laying their eggs in your yard.
This also helps because the beetle eggs and those baby grubs will often die if they dry out.
In case you’re wondering, there ARE some insecticides and bio-controls you can put down.
I will share a resource with you shortly, so you can see your options.
But again, do your research because some have minimal effects on bees, pets and humans, and others are more toxic.
Oh, and there is one treatment worth mentioning that was popular for a few years, but it hasn’t proven to be all that successful in killing the grubs.
It’s called milky spore — it’s a biological control you apply to your lawn.
It’s shown to have a really LOW effective rate for controlling Japanese beetles, so again, you may want to save your money and skip that one.
And if you want to learn more about this, you can read about it in the helpful resource I’ve promised you.
The Colorado State University Extension has created an up-to-date fact sheet on Japanese beetles.
[Note: You’ll find more resources below too.]
The fact sheet is based on research about Japanese beetles, and it includes a list of specific products to help control the beetles.
I will share upfront, the fact sheet can get a little technical, but it’s still helpful.
So, if you’re interested, check it out.
And if you’d love to feel more confident with flower gardening in Colorado, please click subscribe below [on YouTube].
Go get those beetles, and I’ll see you next time.
More Japanese Beetle resources to help you
- Detailed list of products and controls to manage or kill Japanese beetles and protect your lawn: CSU Extension Fact Sheet on Japanese Beetles
- Helpful list of plants that Japanese beetles like and dislike: How to Keep Japanese Beetles Out of Your Colorado Garden (The Denver Post). Betty Cahill, the garden writer for The Denver Post, is a local Colorado expert on Japanese beetles.