Hollyhocks are biennial or short-lived perennials with big, beautiful blossoms. If you’ve grown them in your garden, you likely know what a long and painstaking process it can be to wait for them to bloom. This longer-than-average wait makes it even more distressing when we see that pests are eating our plants.
The first time I planted hollyhocks, I had no idea what to expect. I thought that they must be fast growers because they are rather large when they flower. You can imagine my disappointment when I learned that they wouldn’t bloom at all that first year. It takes a lot of patience to grow them.
I wish that I could tell you that there aren’t many insects that have a taste for hollyhocks. Sadly, as with many plants in the mallow family, they are popular food for many kinds of wildlife. Let’s talk about some pests you may encounter on your hollyhocks and how you can manage them without missing out on those dazzling flowers.
Hollyhock Weevil
The hollyhock weevil is a night-feeding pest with a preference for these pretty plants. They are small, black beetles with orange or tan legs and a long snout. The females are about 1/4″ long (including their snout) and the males are about half that size.
You’re most likely to see damage from weevils in the summer months; they peak in June and July but can continue to lay eggs until September. They will munch on leaves first, leaving them with a lacy appearance.
When buds form, females puncture them to lay their eggs inside. About three days later, the eggs hatch and tiny white grubs get to work. They burrow into the seed pods and feed on forming seeds.
Weevils are active at night, so this is the prime time for identifying these pests. Hold a sheet of paper beneath the affected part of the plant and shake. The insects will become dislodged and fall off. You can also identify them by the damage they cause to leaves and puncture marks on the bottom of buds.
These weevils only produce one generation per year. Once the larvae pupate, the adults drop to the ground and overwinter beneath the soil. Weevils won’t cause damage to your flowers. However, they can shorten the life of the plant and prevent it from re-seeding.
Hollyhocks are short-lived perennials, so if they don’t re-seed, you’ll have to plant them every two years to keep them in the garden. The best way to prevent a new generation of weevils from cropping up next year is to remove the seed pods before they mature. Immerse them in a bowl of soapy water to kill the grubs.
You can pick the adult weevils off by hand at night and drop them in a bowl of soapy water. This can be tedious, though, and if you miss some, you still have a problem. Neem oil is effective against weevils, and so is insecticidal soap.
If you manage to eradicate the larvae before they demolish the seeds, you can allow your hollyhocks to re-seed. If not, it’s best to remove those seed heads and dispose of them before they mature. This will dramatically reduce the number of plants you have next year, but it will also reduce the number of weevils to contend with.
Japanese Beetle
This invasive species is a problem for more than one type of plant. Japanese beetles don’t discriminate much in the garden. The adults feed on hundreds of species of plants, dining on fruit, flowers, and foliage. Their larvae, or grubs, prefer to chew on the roots of your grass, ruining that lawn you have worked so hard to maintain.
Japanese beetles are native to Japan, where they don’t pose much of a threat. Introduced in the United States in the early 1900s, they proliferated here and are now an issue for gardeners in every East Coast state except Florida. They continue to move West by the millions.
Adult Japanese beetles are easy to identify. They are large at up to 1/2″ long and have a metallic green head and bronze wings. They have a fuzzy abdomen beneath their wings with black and white markings. I think they are pretty, but I live in Florida, so my opinion doesn’t count here.
Their larvae are not pretty. Growing from about 1/8″ to an inch long, these cream-colored crawlers look like your run-of-the-mill grub. They have a distinctive pattern on their underside. The grubs aren’t a problem for hollyhocks, but the adults are.
Beetles will trash the foliage of your plants, leaving them brown and chewed up. They feed on nearly every part of the plant, leaving your plants worse for wear, and damaging pollinator homes and food supply.
The best way to deal with Japanese beetles is prevention. Heading them off at the larval stage is possible. You can do this by attracting birds to the yard which will eat them. Avoid watering your lawn between June and August, this is the time beetles lay eggs in the soil, and they need moisture to survive. Fewer eggs mean fewer insects.
If you start to see these guys show up in the garden, you can pick them off by hand and drop them in soapy water. This might sound morbid, but if you leave the dead beetles lying around the garden, this will help to deter others.
Beetle traps work, but make sure to set them up away from your favorite plants, because they do attract the insects.
Use beneficial nematodes (Heterorhabditis bacteriophora) to remove larvae. Apply two of these treatments two weeks apart in temperate fall or spring weather. The nematodes will prey on any larvae that managed to make it through the summer. You’ll only have to deal with adults in the coming season.
Thankfully, Japanese beetles find certain scents to be repellant. No need to use a pesticide. Companion plant some garlic with your hollyhocks as a deterrent or spray with a solution of cedar oil and water.
Sawfly
Raise your hand if you’ve ever gone to battle against sawfly larvae! I know just how aggravating these pests can be and how much damage they can do. One day, your leaves will be healthy, green, and robust. The next, a brown, hole-covered mess.
Sawflies are common garden pests that use their saw-like ovipositor to cut into leaves where they lay their eggs. Adult sawflies aren’t much of an issue to foliage, but their larvae are brutal. They can skeletonize a leaf in no time at all, they work in groups, and they eat a lot. The good news is that if you catch them, it’s easy to get rid of them. They don’t have to be a death sentence.
Sawfly larvae are easy to ID. You’ll see signs of them right away, as they skeletonize the leaves of your plants, seemingly overnight. If you notice this happening to a plant, flip over a leaf that is only half devoured. Small black and brown larvae look like tiny caterpillars. They usually work in groups, defoliating anything within reach.
The best prevention for sawflies and their larvae are natural predators. Attract insects like lacewings to the garden by planting lots of nectar-rich flowers. The larvae of ladybugs and lacewings will knock out an infestation faster than you can, and more thoroughly.
Hand removal is effective for these pests. You can try picking them off by hand, but I recommend pruning instead. When you see signs of them on a plant, start looking under leaves and cut off any leaves where you find them. Dispose of the leaves away from other plants. Chickens love to eat these pests.
You can also dust your plants with diatomaceous earth or kaolin clay to get rid of and deter sawfly larvae. You’ll have to reapply both in humid climates and after rain. I typically discourage the use of pesticides if you can help it, as these kill beneficial insects with the bad ones. This can throw off the balance and leave you with even bigger issues. However, neem and horticultural oils work.
Caterpillar
When it comes to caterpillars, I adopt a “live-and-let-live” attitude. However, you may find them very frustrating, and technically, they are an insect that eats hollyhocks, so we should at least identify them.
Hollyhocks are a host plant for the painted lady butterfly. They lay their eggs on the leaves, and when they hatch, their larvae feed on them. You have to make this decision for yourself. As an avid pollinator enthusiast, I am willing to sacrifice foliage for butterflies. But I understand that not everyone feels that way, so we will address them as pests, all the same.
Painted lady butterflies are pretty little things. They are a small species with orange and black wings and white markings. If you see them hanging around your plants, you’re likely to have some caterpillars hatching in just under a week.
The caterpillars are small and gray with black markings and hairs that stand out in little spikes all over. They also have faint yellow striping that runs horizontally across their bodies. They usually start at the edges of leaves and leave little behind but the central rib.
Prevention is difficult. Butterflies are attracted to nectar-rich flowers. You can always treat your entire garden with systemic pesticides, but pollinators are the backbone of the flower garden. Without them, we don’t have nearly as many flowers. They won’t harm the flowers, only the foliage and their presence means you’ll have more plants in the coming years.
If you must, hand removal is the best way to eradicate caterpillars. They may look a little intimidating with their spiky clumps of hair, but they are completely harmless to touch. Just pluck them off and relocate them. Or, dispose of them in your chosen method.
Scale
Scale insects, on the other hand, have no pretty butterfly stage. I have no affection for these strange little pests that tend to be resistant to traditional methods. Scales are common garden pests that congregate on stems and under leaves, really anywhere on the foliage. They pierce the membrane and suck out the sap, depleting the host of nutrients and moisture.
The severity of the damage depends on the type of scale, and how abundant they are. Some can kill a plant very quickly, while others may not do any serious harm. That’s not a chance I like to take, so I get rid of them when I see them.
Some scales look like tiny, gelatinous blobs affixed to leaves. You probably won’t see them moving around much, because once they latch on they spend most of their time feeding. They tend to cluster up in groups, which makes them easier to identify. They can be brown, yellow, tan, or white.
The best way to prevent these insects is to practice good hygiene. Clean up around the base of your beds and regularly inspect for signs of pests. A sticky excrement called honeydew is usually leftover on the leaves and stems these guys munch on. Black sooty mold can grow in this honeydew, inhibiting photosynthesis and further harming the plant.
Attract beneficial insects to the yard with plenty of nectar sources. These predators do the best job of keeping your garden pest populations down without harsh chemicals. Finally, keep your plants strong. This way they have a better chance of withstanding the damage until you eradicate the scales.
Applying broad-spectrum insecticides is not a preferred method with these or any pests. The reason is that they also kill the populations of beneficial insects. Then you have no natural protection from the nuisance insects.
If the infestation is small and localized, a Q-tip soaked in alcohol is a good tool for removal. Simply use the cotton swab to wipe them off. If the infestation is more extreme, neem oil and horticultural oils are valid treatments. Horticultural oil is best applied in late winter, while the scales are dormant. This is when the crawlers, or young scales, are active and easy to kill.
Spider Mite
I don’t wish a spider mite infestation on any gardener. These pests can be particularly troublesome on houseplants because of the lack of predators in the home. They have plenty of natural predators in the garden, so they don’t take over in the same way, but they are still a nuisance.
Spider mites cause similar issues to scales. They pierce the membranes of the leaves and suck out the sap, damaging overall health. They are so tiny, that they often go unnoticed until the damage becomes obvious. A small infestation is unlikely to harm a mature hollyhock, but a large infestation can.
Because spider mites are so small, they are difficult to detect on their own. Fortunately, they build fine webbing under leaves and in other sheltered locations on the plants they infest. Look in the junctures between leaves and stems, and other places that would provide shelter. If you see this webbing, you likely have spider mites.
In terms of what they do to their prey, leaves may turn bronze on top. Small white or yellow dots may pop up on the foliage. Certain plants may have distorted foliage, especially new leaves. Leaves will drop in late stages.
Good hygiene is important in preventing spider mites. Keep your beds cleaned up and tidy. Spider mites don’t like humidity, so they are mainly an issue in the dry months. Keep your plants watered properly, as water-stressed plants are more susceptible to damage.
Spider mites can be a challenge to get rid of once they establish a population on a plant. Misting them with rubbing alcohol is a reliable way to kill them. Cinnamon, mint, neem oil work too. and Doing this will often dry out your hollyhocks though, so don’t leave the alcohol on for long.
A strong spray of water will knock down the population of mites, but not altogether. Miticides are a better option than other insecticides, as spider mites can quickly become resistant to them.
Mealybug
Mealybugs are little white, sap-sucking pests with a fuzzy appearance. The fuzz is actually a waxy coating, which makes these insects more resistant to pesticides. As another species of scale, they have very similar behavior. They congregate on foliage and leave behind a sticky mess, draining the host of nutrients. These are a threat to the overall health of the plant and will need to be handled to keep it alive.
Mealybugs are easy to see and identify, and tough to get rid of. They are small, oblong insects that appear to have a fuzzy coating of hair, but in fact, they are not. This is their waxy defensive coating. You will find them in groups along stems or under leaves. They also tend to hide in leaf junctures. You’ll find cottony masses of eggs on the plant as well.
Fortunately, mealybugs have a number of natural predators. Attracting these predatory insects to the garden will go a long way toward preventing an infestation. In fact, I’ve dealt with these guys on a houseplant before, and simply setting the plant outside for a few days took care of the situation.
Always inspect new plants that you introduce to your yard. Make sure that you’re not inadvertently introducing pests along with them. Keep your hollyhocks well-maintained and they will stand up better to an infestation.
Insecticidal soaps are better at breaking down the waxy coating than systemic pesticides. Neem oil is another good treatment for mealybugs. As with some scales, a cotton ball soaked in alcohol will also kill them as you wipe them away.
Key Takeaways
Good hygiene in the garden is the best way to prevent pests from attacking your hollyhocks. Keep the areas beneath your plants tidy, and inspect any new plants for signs of infestation. Hollyhocks are gorgeous biennials that will flower beautifully with the right care. They are well worth the effort in keeping them pest-free.
