The long awaited guide to pests and beneficials in the rose garden has arrived! This is a fairly comprehensive list of what you should expect to see in your garden. One of the most important rules to remember is your beneficials are your predators, the pests you deal with are prey. In nature, prey outnumbers predators exponentially. If you use harsh systemic chemicals that are indiscriminate, you will kill both the pests and the beneficials. However, since pests (the prey) have such large populations, they rebound much quicker, and now without the predators to keep them in check!
Something to keep in mind is that there are no specific plants that ATTRACT beneficials, however, there are many that are ideal for planting due to their high nectar and other various benefits. We always recommend, find some native plants and plant those! Other plants that beneficials tend to love: yarrow, alyssum, salvia, herbs like cilantro and dill, goldenrod, marigolds, sunflowers, gaura, and milkweed. Many times adult beneficials will feed on nectar and pollen, and it's the larvae that feed on the pests.
The main thing that makes or breaks habitat for beneficials is a water source. This is a MUST. Period. You must have some source of water, or they will not stick around. A bird bath, a fountain, a small pond, even a shallow dish you fill daily. They need water, just like you and me.
And finally, the other thing that attracts beneficials into your garden are-
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PESTS. Yes, those pests that are so frustrating are what attracts the beneficials to your garden. It's their food source, and without food present, they move on. It's important to leave some pests to feed on, otherwise they will bypass your house entirely.
*Note*- Under each pest we list the beneficials that take care of them, as well as alternate methods to deal with them. For a more expanded approach on these methods or for more information about each beneficial, scroll past the PESTS section and find the corresponding information.
Pests
Photo thanks to Farmer’s Almanac
Aphids:
Aphids are the number one most common pest. There are over 4,000 species of aphids, 250 of which are major pests for crops and ornamental plants. They can come in a variety of colors, from green to brown, even to fuzzy and white! Aphids, like many other pests, suck the sap out of your plant. You will notice crinkled leaves and distorted growth. You will likely also notice the aphids themselves clustered around new growth, which is their favorite. On top of sucking the juices from your plants, you may also notice a sticky substance on your leaves and stems. This is their excretions, which is called honeydew. Honeydew can cause fungal issues for your plant. Aphids have a symbiotic relationship with ants. Ants will actually farm the aphids for the honeydew. They will transport them from stem to stem, as well as protect them from predators. If you notice aphids and ants, it’s best to get involved with some alternative methods to help make sure the beneficials aren’t getting overrun. All this said, aphids are almost endemic, meaning they exist pretty much everywhere. If you have a plant they like, you will get them pretty much no matter what you do! But the good news is, most EVERYTHING eats them. They’re an important food source, and I always say, if you have no aphids, you won’t have any beneficials to take care of the much worse baddies later.
Alternative Methods: Squish ‘Em, Spray ‘Em, Neem Oil, Insecticidal Soap
Whiteflies:
Whiteflies can be a frustrating pest. They are a soft bodied insect (they’re related to aphids) but unlike aphids who don’t move much, whiteflies are agile and very fast. This makes it difficult to control them. Whiteflies suck sap from the bottom sides of the leaves, making it difficult to spot them until they have a huge population, and they can be very damaging to your plant. Whiteflies are best controlled by parasitic wasps.
Alternative Methods: Spray ’Em, Neem Oil, Spinosad
Caterpillars:
Good ol’ caterpillars. When they turn into butterflies, we love them as our pollinating friends. Unfortunately, many types of moths lay eggs that turn into cutworms and army worms, which can quickly decimate the buds and leaves of your roses. Populations can unfold quickly, and can be hard to spot as the caterpillars roll leaves into tiny tents and burrow into buds. However, the damage is quickly noticeable with tattered blooms and holes in leaves. Thankfully, caterpillars are a rare, juicy meal for many beneficials. They are prized for food by birds, wasps, dragonflies, robber flies, assassin bugs, lizards, spiders, frogs, and toads. There are also parasitic wasps that will prey upon caterpillars.
Alternative Methods: Squish ’Em, BT
Beetles:
Beetles. That one word is the bane of many gardeners existence. While thankfully beetles rarely compromise the health of a plant, even in large numbers, they can definitely cause mass carnage to buds and blooms. There are many types of beetles, including June Bugs, Cucumber Beetles, Japanese Beetles, Rose Chafers, and various other species. Beetles are eaten by larger predators, such as birds, lizards, spiders, assassin bugs, wasps, and praying mantids. It is important to understand their life cycle, which is the young exist underground as grubs. Beneficial nematodes can help with beetle larvae.
Alternative Methods: Dunk ‘Em
Spider Mites:
So far on this list we haven’t seen anything that is likely to kill your rose. That changes now. Spider mites are one of the most destructive pest, just based upon sheer number and an insatiable appetite. The first signs of spider mites are oddly discolored, stippled leaves, and at more mature stages, webbing around the leaves of your plant. It may also feel “dusty“ to the touch. Spider mites can and do kill plants, so it is extremely important to take care of them as soon as you see signs. The best control is predatory mites, as well as making sure your rose is well watered. Spider mites dislike wet environments. If you don’t have predatory mites yet, and you have spider mites, I highly recommend using alternative methods to destroy the population BEFORE releasing beneficials.
Alternative Methods: Spray ‘Em, Defoliate, Rotation Spray
Rose Slugs/Sawfly Larvae:
Sawfly larvae (also called rose slugs) look like caterpillars but are actually closer related to wasps, bees, and ants. This means that BT, which kills caterpillars only, unfortunately does not affect them at all. These voracious eaters can strip your rose bare in a very short time period. Sawflies are luckily very easy to see, as their damage is very apparent right away. Many beneficials feed on these juicy larvae, including birds, lizards, and wasps. Spinosad is typically the most effective alternative method besides squishing and dunking! Make sure you check the undersides of the leaves, and if necessary, spray both top and bottom sides of the leaves.
Alternative Methods: Squish ‘Em, Dunk ‘Em, Neem Oil, Spinosad, Insecticidal Soap
Thrips:
Thrips are the nemesis of any gardener looking to enjoy the blooms. There are two primary species of thrips here in the US: the western flower thrip and chili thrips. Each causes different damage and must be controlled differently.
Western flower thrips attack buds and blooms. You will notice brown edges of petals and disfigured blooms. When the bloom is open, you can see these pests by pulling back the petals and looking towards the center of the bloom. They are small, long creatures. Thrips suck the juices from the petals.
Chili thrips are a much worse pest. Not only do they attack blooms and buds like the western flower thrip, they also unfortunately attack the foliage of your plant, causing extreme distortion and little black “scorch” marks on the leaves. Thrips are extremely resilient, and can become resistant to pesticides. For this reason, we recommend a spray cycle, and then releasing beneficials. Minute pirate bugs are voracious thrip predators, and predatory mites will eat immature thrips as well. Lacewings and ladybugs do also feed upon thrips, but are not the most efficient predators as they tend to go for larger prey.
Alternative Methods: Defoliate, Remove Blooms, Rotation Spray
Rose Midge:
Rose midge are pests you’ll likely never see. They resemble tiny mosquitos, and have a very short lifespan. Luckily, rose midge are not very common pests, but if you keep having buds turn black and fall off, you may have a midge issue. The females lay their eggs into the buds, and the pupae eat through the tissue. Unfortunately I do not know of a predator that is efficient for rose midge. Alternative methods are the best course of action.
Alternative Methods: Remove Blooms, Rotation Spray
Cane Borers:
Cane borers decimated my garden last year. There are several species of insects that bore into canes, but the results are the same. The adult drills a hole into the center of a cane, usually through an open pruning wound. They lay their young into the hole, and the larvae eat the center pith of the cane.
This causes extreme damage to the plant. The cane with the borer will experience dieback, and sometimes the larvae will even eat into the crown of the plant. Borers can kill your roses. Since borers are a variety of species, there’s not really any beneficial specifically that will take care of the issue. We recommend using alternative methods to deal with borers.
Alternative Methods: Prune n’ Seal
Grasshopper/Crickets/Planthoppers:
Grasshoppers, crickets, and planthoppers are common pests that eats pretty much every part of your rose! They love munching on anything they can get their mouths on. These are larger insects, capable of doing large amounts of damage by themselves. Thankfully, big and juicy means that they are a great meal for lots of larger beneficials. Birds, wasps, praying mantids, dragonflies, assassin bugs, robberflies, lizards, spiders, toads, frogs, even snakes will munch on these baddies. I highly recommend squishing them when you see them to keep the population in check.
Alternative Methods: Squish ‘Em, Neem Oil
Rabbit and Deer:
Unfortunately, rabbit and deer are common pests to deal with in the garden. Apart from attracting coyotes and hawks to your garden, there’s not much you can do beneficial wise to help prevent and reduce these pests damage. Both creatures love roses, so the best course of action is to build fencing, as well as plant extremely fragrant and herbal smelling plants around your roses. Add things with sticky, fuzzy leaves to your garden. The more unpleasant texture and unpalatable things, the less likely they will take up residence. Consider using deterrents like coyote urine.
Beneficials
Ladybugs:
Ladybugs have many variations, but all ladybugs are voracious eaters of many soft bodied insects. Adults can eat up to 50 aphids a day, and their larvae (which look like little black and orange alligators) are even hungrier! They eat 3-4x the amount their parents do. The eggs will be yellow-orange colored and be attached to the backside of leaves. To encourage ladybugs, leave leaf litter in the garden until temperatures get above 60°F consistently. If you release ladybugs, they will likely fly away. As with all beneficials, they need three things to stick around: food, water, and shelter. Plants and roses provide great shelter, but it’s up to you to provide the other two. Have a water source (even something as small as a bird bath) and keep it clean. Let the aphids be, so the ladybugs (and others) will set up shop right in your garden!
Lacewings:
Lacewing adults look like tiny green fairies. The adults feed on pollen, and they do not migrate, so these bugs are a great option to add to your garden for more permanent residents. Eggs are small and white, attached by a thread to leaves or wood. The larvae are extremely voracious, and will eat most smaller bugs, including thrips, aphids, spider mites, etc. As with all beneficials, having food, shelter, and water are key to keeping them around. Provide food for the larvae AND the adults!
Minute Pirate Bugs:
Adults are very small and look like tiny winged beetles. Pirate bugs are no joke, and are voracious eaters. Their favorite food is thrips, but will also feed on mites and other small insects and eggs, as well as pollen if no insects are available. All stages are predatory.
Predatory Mites:
There are several species of predatory mites. Predatory mites mainly feed upon other mites that are pests, but occasionally will eat other immature pests (like a. cucumeris with thrip larvae). They multiply rapidly as long as they have a food source, and are very easy to obtain. High numbers are required per plant, but they are relatively cheap to obtain.
Assassin Bugs:
These scary looking insects are highly predatory, and will use their mouth to piece and eat many types of pests, including larger sized pests.
Praying Mantis:
Praying mantis are non-discriminatory hunters, meaning they will eat anything they can get their hands on and fit in their mouths. This unfortunately includes bees and butterflies, but don’t be sad that nature balances itself. Be happy for the hundreds of bad bugs they eat! Really, they eat so many! I recommend searching out the native mantis types, as they are smaller and less likely to consume beneficials.
Wasps:
While most people are scared of wasps, I rejoice at the sight. They’re great aphid control, and also eat larger pests like grasshoppers and caterpillars. Wasps can remember faces, so just be sure not to swat at them or freak out. Having a paper wasp nest in your garden can save you a lot of headache later in the year! Wasps are not as aggressive as hornets or yellow jackets, and can peacefully coexist in your garden.
Parasitic Wasps:
Parasitic wasps do not sting, but are host specific. Just like monarch caterpillars only eat milkweed, parasitic wasps have favorite pests to eat. They lay their eggs in the pest of choice, and the larvae hatch and eat the pest. They are usually very tiny.
Dragonflies:
Many do not realize that dragonflies are top predators in the insect world. Like praying mantis, dragonflies are apex predators, so don't be surprised if you see them snacking on all types of insects, from caterpillars, young grasshoppers, beetles, flies, bees, even sometimes small butterflies and moths. Dragonflies are also the main predator for mosquitoes. Dragonflies are especially helpful against flying pests. If you have the room, adding a small but deep pond will help attract these top notch predators to your garden.
Birds:
Birds are often overlooked as a beneficial, but many smaller species of birds frequently eat smaller insects. Beetles and caterpillars are juicy treats, and first thing in spring, tiny birds like chickadees and finches feed on aphids. Create inviting spaces for birds by adding bird baths, bird houses, and putting up feeders (but don’t always keep them full, or they’ll never eat the insects!)
