Hydrangeas, what’s not to love about these big, bushy shrubs with their bold foliage and huge flower clusters that look like a cheerleader’s pom-poms? They are easy to grow, are fast-growing plants, and make great cut flowers that last a long time. Lately, though you have noticed some damage on them you wonder, “what is eating my hydrangea?”
Many types of insects and bugs feast on hydrangeas, such as slugs, caterpillars, beetles, aphids, and spider mites. To get rid of these pests, you need to know what bugs you are dealing with and what kind of damage they do. Then you can treat the problem with the correct eradication methods.
While some pests will do minimal damage to your hydrangeas, others can completely ruin your plants. Keep reading to find out what insects are eating your hydrangeas and how to get rid of them.
1. Slugs And Snails
While you might not see slugs or snails on your hydrangeas because they like to come out on humid nights, you’ll notice their slime trails when they sparkle in the sun. The damage they cause looks like ragged edges ripped from the leaves or holes in them.
Slugs typically eat the leaves and leave the flowers alone. They also like softer, new leaves better than older, tougher ones, but that doesn’t mean they won’t attack big, full foliage.
Physically Remove Snails And Slugs From Hydrangeas
When you see the slimy gastropods on your hydrangeas, you can pluck them off and drop them in a bucket of soapy water to eliminate them. If the thought of touching these slimy, wriggling creatures turns your stomach, put on some garden gloves or you can spray them off with a garden hose.
While removing them physically is one way to deal with them, they are more active at night, and you’ll inevitably miss some unless you stay up all night picking them off. The best way to treat slugs is to keep them from getting to your plants in the first place. You can do this in many ways.
If you’re wondering where these sneaky mollusks hide, read our article on the places slugs come from at night.
Use Copper To Deter Slugs
Whether you use pennies, copper tape, or wire, when a slug touches anything copper, it gets an electric shock. The slime they use to move around conducts electricity when it touches copper so they can’t pass this metal.
You can use LOVIMAG Copper Foil Tape to keep these gastropods from entering your garden. You can also use copper wire to create a barrier by wrapping it around your plants or garden.
Pennies can even work to keep slugs and snails away. Just place them together in a consecutive line, leave no gaps, or they will get through. You may have to attach them with an adhesive to keep the pennies from getting washed away or accidentally moved.
Use Salt To Dry Snails And Slugs Out
Snails and salt don’t mix, so leaving a barrier with salt is a great way to keep these pests away. As soon as they touch salt, it causes them to bubble up as the salt drains the water from their body.
Sprinkling a line of Epsom salt is a great way to tell snails and slugs they have outstayed their welcome. They cannot pass over the salt and they’ll leave that area alone. The Epsom salt will have to be replaced occasionally as it dissolves.
Mulch Slows Slugs And Snails Down
Bark chips, gravel, or shredded hardwood mulch are sharp and painful for these soft-bodied gastropods to pass over, so adding a fresh layer of mulch will also deter them from getting to your plants.
You can use eggshells in a similar manner, as the sharp edges of the shell make it difficult for snails and slugs to pass over.
Remove Attractants To Repel Slugs
Slugs typically eat decaying leaves and vegetable matter, so cleaning up the area underneath your hydrangeas of old leaves or rotting organic material will keep from attracting these pests to your plants.
You can read more about snail attractants in our guide on the reasons snails are in your garden.
Snails And Slugs Hate Coffee Grounds
What can you do with the leftover coffee grounds after your morning cup o’ joe? Spread them around your hydrangeas. Used coffee grounds will help add a bit of acidity to the soil which hydrangeas love and they repel snails and slugs.
A lot of gardeners report mixed findings using coffee grounds, but the USDA reports that the caffeine in coffee works great to eliminate and repel slugs. In soil that was infested with snails, a spray of caffeinated water got rid of 95% of the snails in the soil.
If you find that the coffee grounds aren’t cutting it, spray the ground with a coffee and water solution and see if that gets rid of your slug or snail problem. You’ll probably have to reapply every few days or after a rain to make sure the caffeine is effective.
Buy Slugs And Snails A Beer
A tried and true method for getting slugs and snails is to use a beer trap. They love beer, but they just can’t hold their alcohol at all.
All you have to do is dig a shallow dish into the ground so only a small lip is sticking above the ground. Then pour some beer into the container—pour enough beer in that will cover the slugs. The slugs are attracted to the yeast smell, but when they hit the beer, they fall in and perish.
Use Repellent Plants To Keep Mollusks Away
Slugs and snails don’t like strong fragrances, either. Plants and herbs that are very fragrant repel these gastropods. Since lavender is one of the most fragrant herbs that are found in nearly every nursery, plant some around your garden.
Other plants that repel these pests include marigolds, sage, thyme, and rosemary. Mint works too, but if you plant mint in the ground, it will soon take over your yard, and probably the neighborhood too. Check out our article on whether french marigolds really repel slugs here.
You can read more about the scents that snails hate here!
Everyone who has planted something in the ground has probably come across this prolific garden pest at one time or another. Aphids seem to show up wherever new plants get put into the ground. They spread incredibly fast, and a single colony can dry out whole plants.
Aphids are tiny, soft-bodied insects that suck the sap from plants. They have long antennae, are usually light green, brown, or black, and sometimes have small wings. These slow-moving insects often congregate on the undersides of leaves and at the stems in large numbers.
Signs of Aphid Damage On Hydrangeas
Aphid damage may appear as yellowing of your hydrangea’s leaves, or the edges will curl and turn brown. If you notice this happening, turn the leaf over and you may see the pests crawling all over it.
Use Natural Predators To Repel Aphids
One of the best ways to treat aphids is to use natural predators. Ladybugs and green lacewings, especially their larvae as they can’t fly away, are wonderful, all-natural ways to eradicate aphids. Get some live ladybugs to eat away the aphids such as Clark&Co Organic 3000 Live Ladybugs.
Spray Aphids With A Garden Hose
To get rid of aphids right away, you can spray them off with a strong jet of water from your water hose. Spraying the aphids will knock them loose from your plants and most times damage their soft bodies so they don’t come back.
Unfortunately, this isn’t a permanent fix, as some will survive and could infest other plants or come back.
Insecticidal Soaps & DIY Sprays Will Repel Aphids
Insecticidal soaps work wonders for controlling aphids. You can make your own by mixing up a cup of oil (vegetable, corn, olive, etc.) and a tablespoon of regular, plain dish soap.
Steer clear of bleach additives or other “extras” as these could damage your plants. Then add three tablespoons of this mixture to a 24-ounce spray bottle of clean water. We have a fantastic guide on the best aphid repellents here!
Here are a few extra tips:
- Extra Strength: To give this spray some extra repelling effects, add a few drops of garlic or pepper oil to your spray bottle mixture of insecticidal soap. The smell will help to repel many other insects and pests.
- Test First: Before soaking your whole plant, test the mixture on a small area of your hydrangea to make sure it will not harm it. When you know it’s safe, spray the aphids, making sure you get the bottoms of the leaves where they like to hide. You may have to apply the spray a few times to take care of all the aphids.
- Apply In The Morning: Be sure to apply in the morning when the insects are just stirring, and it’s not scorching hot outside yet. The oils and soaps in the spray could damage the plant if it’s applied during the heat of the day.
To find out more about aphids and plenty of ways to treat them, check out this post on Reasons Why Aphids Keep Coming Back.
They sure do like to eat hydrangeas, especially Japanese beetles. There are so many different species of beetles that will feed on hydrangeas that we will group them all into this one section. The damage and treatment of beetles on these plants are very similar.
Beetle damage to hydrangeas often looks like something took all the green from the leaf and left behind the veins. Basically, it looks like a leaf skeleton. You’ll probably see the beetles crawling or flying around the plant.
Pick Beetles Off Hydrangeas By Hand
One way to treat beetles on your hydrangeas is to pick them off by hand. Most beetles are pretty slow-moving until they fly away. Have a bucket of soapy water nearby and drop the beetles in the bucket to eliminate them.
The soap makes them sink to the bottom, otherwise, they would just float on the top of the water until they either crawl out or fly away.
If Japanese beetles are your main issue, you can read about the scents Japanese beetles hate for more ideas on how to repel these pests.
Don’t Use Beetle Traps!
Hanging beetle traps are sold everywhere you find pest control measures, but don’t use them! These traps contain pheromones that can attract beetles from far and wide, and you could end up attracting every beetle in a country mile to your house!
Your neighbors will thank you, but then you’ll have thousands of beetles to take care of.
Get Rid Of Grubs Before They Turn Into Beetles
Another way to prevent Japanese beetles is to treat the ground if you find grubs. Those pulsating, disgusting-looking worms with tiny legs are beetle larvae. They live in the ground eating roots until they morph into beetles and escape the ground.
If you find grubs in your ground when digging, treat your yard with milky spore. This material is safe for plants, pets, and humans, but will get rid of the grubs in the ground. You can read more about how to exterminate these pesky grubs in our article on the simple ways to get rid of leaf beetle larvae.
Use Neem Oil Spray To Repel Beetles
To treat adult beetles and other insects, use Natria Neem Oil Spray. Be careful when using this while hydrangeas are blooming as it can harm beneficial pollinators such as honeybees and butterflies.
4. Spider Mites
Another common pest that will dine on your hydrangeas is spider mites. These tiny pests infect plants that are stressed or wilting because of heat and lack of moisture. They create a thin network of webbing to protect themselves and to go from leaf to leaf.
Another sign of spider mites is a speckling across the leaves and flowers of your hydrangeas. This is caused when the spider mites feed on one area and then move to another.
Repel Spider Mites From Your Hydrangeas By Watering Plants Properly
The best way to prevent these tiny mites is to keep your plants watered correctly. Adding mulch can reduce how much you have to water as it helps to keep the ground moist. Also, keep your garden weeded, so there’s no competition for water.
To get rid of spider mites that have set up house on your hydrangea, spray them off with your hose. Most times, this is enough to get rid of them.
Use a soft cloth and a very soft bristle brush to remove the webbing if the hose doesn’t do the trick. If that does not work the first time, you may have to spray them again.
When spraying with a hose isn’t enough to evict these web-slinging mites, use the homemade insecticidal soap from earlier in the article, or spray them with neem oil.
Caterpillars will eat large sections of your hydrangea if you give them free rein. The most popular caterpillar that affects hydrangeas is the leaftier because the moths will lay eggs on the plants. You notice these pests when they curl up a few leaves with their silk strands.
When these caterpillars hatch, they wrap themselves in a leafy cocoon and eat the leaves inside it. As they grow, they’ll wrap up more leaves. The damage is easily spotted and treatment is fairly easy.
Get Rid Of Caterpillars On Hydrangeas By Snipping Off Affected Branches
When you notice the silk-covered leaves curled in on each other, just snip the branch off near the next leaf nodes and throw it away, or squish the caterpillars inside. Insecticide sprays probably won’t be very effective in treating these caterpillars because they are so entrenched in the leaves.
Snipping off the affected leaves is the best way to get rid of them. When these caterpillars are ready to pupate, they will drop to the ground until they complete their metamorphosis. Then the moths will mate and lay their eggs back on the hydrangea to complete their cycle.
Getting rid of the little worms before they can transform into moths will stop the cycle. This is the best way to prevent their recurrence. Just be sure to go over your whole hydrangea carefully because there could be 15 or 20 caterpillars on one plant.
You can also remove the things in your yard that may be attracting caterpillars to your beautiful hydrangeas.
Scale sounds like some kind of fungal disease, but it’s a sap-sucking insect like aphids and spider mites. The difference is when the scale attaches itself to the plant; it becomes permanently attached, making it look like the plant has a nasty-looking disease.
Scale usually isn’t fatal for the plants, but the spots on the leaves can look awful, and they can return year after year if not treated.
How To Remove Scale Before It’s Attached
Once scale insects have attached themselves to your plant’s leaves, they create a hard shell covering that is difficult to remove without removing the leaf. Even if it’s sprayed and is no longer living, it will remain stuck to the leaf.
One way to prevent them or to treat scale insects before they attach to the leaves is to invite ladybugs to your garden. You can read how to do this in our article on the different ways to attract ladybugs to your garden. Not only will ladybugs eat aphids, but they’ll also munch on scale insects before they have “glued” themselves to the bottoms of the leaves.
When they’re moving around, you can spray scale insects with insecticidal soaps or neem oil to get rid of them.
How To Remove Scale After It’s Attached
Once they have become attached to the leaves, the best way to get rid of them is to cut the infected leaves off the plant. Search the plant and the ground in case any infected leaves have fallen to the ground. When you get all the scale-infected leaves off, throw them in the trash or burn them if that’s allowed in your area.
To prevent a recurrence of scale, keep your plants as healthy as possible. A healthy plant is the best insurance policy against scale infection. Make sure your hydrangea is well watered, the ground is clean and weeded, and it’s mulched.
Stressed and weakened plants attract pests that want to feed on them.
7. Whitefly Nymphs
Whiteflies are more closely related to aphids than actual flies, and they live in warmer climates; USDA zone 7 and higher. Whiteflies are active during the day. They look like small, almost triangular, moth-like insects with white wings.
When they are disturbed, you can see the adults flying out from underneath the leaves where they were hiding. If you find whiteflies late in the season, you might not have to worry about them because they usually can’t survive cold winters.
Signs Of Whitefly Nymph Damage
The nymphs cause the most damage if their numbers are high. Just like aphids, they suck the juices from healthy plants and deposit a sticky substance called honeydew which can attract ants because they eat the honeydew and protect the nymphs.
The sticky honeydew secretion can cause black sooty mold, and the insects themselves can transmit diseases from one plant to another. If they don’t cause these problems, they can shrivel up leaves, and in large enough numbers, they can kill the plant by preventing it from carrying out photosynthesis.
You can learn more about where whiteflies come from and how to get rid of them in our article on the topic!
Whitefly Treatment Is More Crucial For Nymphs
Leaves from whitefly damage will appear wrinkled, dried up, and/or curled. You’ll also notice a glossy, sticky substance. You might also see a lot of ants on your hydrangea plants, as they will work to protect their food source.
Treatment of whiteflies isn’t needed unless you see nymphs on your plants. Adult whiteflies don’t do as much damage as nymphs which suck the sap from leaves. The biggest problem with whitefly nymphs is the honeydew they secrete, as it can cause black sooty mold.
Repel Whiteflies From Hydrangeas With A Garden Hose Or Insecticidal Soap
The treatment and prevention of whiteflies are the same as aphid treatments. You can spray them off with a jet from your hose, or use insecticidal soap to eradicate them. Since they are so prolific, you may have to spray them a few times.
Along with spraying the whitefly nymphs, you can vacuum off adult whiteflies in the morning before they move about. Dump the vacuumed adults into a sealable plastic bag and dispose of them so they can’t lay more eggs and start the cycle all over again.
Snip Affected Parts Of The Plant
Trimming the damaged sections of the plant, and then disposing of the waste in the trash will also help to get rid of whiteflies. Once you have them taken care of, make sure your plant stays healthy by watering it as needed and adding a slow-release fertilizer.
Nematodes are microscopic worms that typically live in the soil all around us. The vast majority of these tiny creatures cause us no harm, but there are a few that can damage plants.
There are beneficial nematodes that help our gardens by getting rid of garden pests like weevils and grubs. You may have even used them before, but some can cause damage to your hydrangeas, such as the root-knot nematode.
Signs Of Nematode Damage
The damage these tiny worms cause often looks like water or nutritional deficiencies. The hydrangea may appear wilted, show discolored and shriveled leaves or slow down growth. If you are taking care of your plant, but it’s exhibiting some of these symptoms, you might have root-knot nematodes.
One way to be sure is to dig up around the roots of your hydrangea and look for galls, or knobby-looking, round growths on the roots. These worms are too small to see with the unaided eye.
Contacting A Professional For Root-Knot Nematodes
While there are chemicals that will eradicate nematodes, most are for commercial applications. They will also destroy beneficial nematodes and good bacteria in the soil. With nothing to protect the soil, this means the “bad” nematodes can just move back in.
You may need to consult with a professional yard company or pest control agency to treat your yard for root-knot nematodes. You can use our nationwide pest control finder to connect with a pest specialist in your area.
Soil Solarization Can Eliminate Nematodes
Don’t despair though, as there are a few things you can do to treat these nasty worms. One action to take is soil solarization. This works better in areas that don’t have any plants growing in the soil.
First, you need to soak the ground well, like you are watering the lawn. Then use a thick, clear, plastic sheeting and cover the ground where you want to treat these roundworms. Finally, leave the sheeting there for about four to six weeks.
The sun will shine through the plastic and heat the soil. The water you added before covering it with the plastic effectively steams the soil like a packet of poached fish.
This gets rid of bad nematodes, fungi, and nearly anything else living in the ground, so you will have to add beneficial bacteria and nematodes back into the ground before planting anything else.
Repel Root-Knot Nematodes With Marigolds
The other option is to plant marigolds wherever you have found or suspect root-knot nematodes. Marigolds secrete a substance that is toxic to these worms. You’re not done after you plant them though.
When the marigolds are finished for the season and are all dried out and nasty-looking, don’t pull them out. You’ll need to till them into the ground for full effectiveness. Doing that puts more of the compound that root-knot nematodes hate back into the ground.
Disinfect Garden Tools To Avoid Spreading Nematodes
Along with either of these methods to get rid of these root-damaging roundworms, disinfect any garden tools you use. This will keep from transplanting these worms into other areas.
9. Black Vine Weevils
Black vine weevils are small, black, flightless insects with a long, frightening-looking hook sticking out from the front of their heads. The adults do minor damage to hydrangeas, as they will only do minor damage to the leaves. The grubs in the soil are the major damage-causing culprits.
Signs Of Black Vine Weevil Damage To Hydrangeas
Black vine weevil grubs can eat the roots of your hydrangea and then move on to eating the tender bark around the base of your plant. If this is not caught in time, the grubs could end up girdling the hydrangea, causing fatal damage.
The problem with the grubs is when the damage is noticed, the plant is probably beyond saving. Damage from black vine weevil grubs looks like the hydrangea is suffering from drought.
Treat The Soil With Beneficial Nematodes To Eliminate Weevil Grubs
Adult black vine weevils are nocturnal, so you might not see them feasting on your hydrangea. To find out if you have these grubs in the ground, move back the layer of mulch and dig into the ground near the roots just a few inches. The grubs won’t be far away from their food source.
They look like normal beetle grubs; white curled bodies, legless, with a brown head. The grubs can survive the winter in the ground and then emerge as adults from May to June. If you see them, you’ll need to treat the soil with beneficial nematodes.
Pesticides don’t work well on adult weevils. They are quite resilient insects. By soaking the soil and adding NaturesGoodGuys Live Beneficial Nematodes Hb+Sc+Sf you can effectively and naturally get rid of many negative grub species, including the black vine weevil.
Before treating with beneficial nematodes, you need to make sure you pull back any mulch so the microscopic worms can get to the soil where they can find the grubs and take care of those pests.
For more information on how to get rid of any type of weevil, check out this list of simple tips to keep weevils out of your garden!
Wrapping It All Up
There are a lot of insect and bug pests out there that want to feast on your hydrangeas. Recognizing the damage they cause is the first step in being able to treat your plants effectively.
To recap, here are the 9 insects that love eating your hydrangeas:
|Typical Damage to Hydrangeas
|Snails & Slugs
|Feed on leaves, stems, and flowers, leaving holes and slime trails
|Suck sap from leaves and tender shoots, causing wilting and distortion
|Chew on leaves and flowers, creating irregular holes and notches
|Feed on leaf undersides, causing stippling and discoloration
|Consume leaves, buds, and flowers, leading to skeletonized foliage
|Pierce plant tissues to feed on sap, causing yellowing and weakening
|Feed on leaf undersides, excreting honeydew and causing leaf yellowing
|Attack roots, leading to stunted growth, wilting, and yellowing
|Black Vine Weevils
|Larvae feed on roots, leading to wilting, yellowing, and eventual plant death
Snails, slugs, caterpillars, and beetles are easy to spot and do very similar damage, but they require different tactics to eradicate them. Aphids, scale, and whiteflies can be treated with a jet from a hose or a concoction of insecticidal soap. Now you’re armed with the knowledge to treat each problem and keep your hydrangeas healthy and pest-free!
Ansari, M. A., F. A. Shah, and T. M. Butt. “Combined use of entomopathogenic nematodes and Metarhizium anisopliae as a new approach for black vine weevil, Otiorhynchus sulcatus, control.” Entomologia experimentalis et applicata 129.3 (2008): 340-347.
Bridge, J., and S. L. J. Page. “Estimation of root-knot nematode infestation levels on roots using a rating chart.” International journal of pest management 26.3 (1980): 296-298.
Abad, Pierre, et al. “Root-knot nematode parasitism and host response: molecular basis of a sophisticated interaction.” Molecular plant pathology 4.4 (2003): 217-224.
Hata, Trent Y., Arnold H. Hara, and Benjamin K-S. Hu. “Molluscicides and mechanical barriers against slugs, Vaginula plebeia Fischer and Veronicella cubensis (Pfeiffer)(Stylommatophora: Veronicellidae).” Crop Protection 16.6 (1997): 501-506.
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