Courtesy Mary BrighamDamaged hibiscus leaf
Why Japanese Beetles Are So Destructive
Japanese beetles didn’t start here. Native to Japan, they first showed up in the U.S. in 1916, likely hitchhiking in the soil of imported iris plants near Riverton, New Jersey. “When I began my career, they weren’t even in the Midwest yet,” recalls Tom. “By the 1990s, we started seeing them in good numbers. Once they’re established as a new critter in town, they’ll be there forever.”
Without natural predators to keep them in check, the beetles spread quickly. Today, they’re found across most of the eastern and midwestern U.S., with populations creeping west.
Japanese beetles deliver a double whammy: Adults feed on trees, shrubs, perennials and annuals while simultaneously laying eggs in lawns. The grubs that hatch chew through grassroots, and hungry skunks and raccoons often dig up turf to get to them.
Their feeding behavior makes things worse. “They like to congregate,” Tom explains. “One beetle finds a good food source, releases a pheromone and suddenly you’ve got dozens feeding, mating and multiplying in the same spot.”
The damage is mostly aesthetic, but it’s hard to ignore.
Mike Hill Photography/Getty ImagesCloseup of Japanese beetles feeding on a yellow rose
Some Plants Repel Japanese Beetles
Roses, grapes and linden trees will always be on their menu, but strategic planting can tip the balance. “You’ll never eliminate them,” Tom says. “But you can make smarter choices. Plant less-favored species, and you won’t be fighting the beetles every summer.”
Along with hand-scooping beetles into soapy water in the cool morning — Tom’s go-to non-chemical control — one of the easiest tactics is to lean on plants beetles dislike. Interplanting resistant species among vulnerable favorites or swapping in alternatives altogether can make your landscape far less inviting.
The reason beetles pass over certain plants often comes down to chemistry and texture. Strong scents, bitter-tasting compounds, and tough or fuzzy leaves discourage feeding. Some flowers, like geraniums, even contain compounds that temporarily paralyze beetles when eaten.
Tom’s research on roses also showed how nuanced their feeding habits can be. Knock Out roses, often touted as resistant, still got nibbled. “In a no-choice situation, beetles will eat them,” he says. “But when given other rose options, they definitely show preferences.” This means, plant several rose varieties in addition to Knock Outs; your Knock Outs may be spared.
Here are 10 plants that Japanese beetles rarely bother, each bringing its own color, texture or fragrance to the garden.
Courtesy Susan Collins
Catnip
Nepeta cataria, Zones 3 to 9
Its pungent oils act like natural repellents. Japanese beetles give it a wide berth, while pollinators and neighborhood cats find it irresistible. Use it as a low-maintenance ground cover in sunny, dry spots.
Courtesy Susan Voelker
Chives
Allium schoenoprasum, Zones 3 to 9
Members of the onion family contain sulfur compounds that beetles dislike. “Anything with that onion-garlic chemistry is unappealing to them,” says Tom. Clumps of grassy foliage and purple pom-pom flowers also make chives ornamental as well as edible.
Psst—roses love garlic: here’s why.
Courtesy James Kurzynski
Lantana
Lantana camara, Zones 8 to 11; annual in cooler regions
With tough, aromatic foliage, lantana doesn’t tempt Japanese beetles. But butterflies and hummingbirds love its fiery-hued flower clusters. Plant it in containers or beds for nonstop summer color.
Courtesy Bruce Fenster
Marigold
Tagetes spp., annual in most zones
Marigolds’ pungent scent is famous for keeping pests at bay. “It’s a classic companion plant,” says Tom. Interplant marigolds with vegetables or line flower borders to create a natural barrier of plants to repel Japanese beetles.
RDA-GID
Boxwood
Buxus spp., Zones 5 to 9
Dense evergreen foliage makes boxwood unappetizing to Japanese beetles. The same is true for hemlock, pines and junipers. They offer structure and greenery in the landscape without becoming a beetle buffet.
nickkurzenko/Getty Images
Magnolia
Magnolia spp., Zones 4 to 9 depending on species
Thick, leathery leaves aren’t easy for beetles to chew, so magnolias generally escape damage. Their spectacular spring blooms are a bonus.
Courtesy Emily Banks
Lilac
Syringa vulgaris, Zones 3 to 7
Known for their intoxicating fragrance and billowy spring blossoms, lilacs are typically ignored by beetles. They thrive in full sun and bring early-season beauty to the garden.
Courtesy Sandra Hough
Dusty Miller
Jacobaea maritima, Zones 7 to 10; annual elsewhere
The fuzzy, silvery leaves of dusty miller are bitter and unappealing to beetles. Use them as striking contrast in beds and borders; they hold up beautifully in heat.
Learn how to get rid of rose chafer beetles.
Courtesy Sjef Van Der Ven
Coreopsis
Coreopsis spp., Zones 4 to 9
This drought-tolerant perennial delivers a carpet of daisy-like blooms in yellows and reds. Pollinators flock to coreopsis, but Japanese beetles look elsewhere for a meal.
Geraint Rowland Photography/Getty Images
Geranium
Pelargonium spp., annual
An odd case: Japanese beetles are attracted to geranium blooms, but the petals contain a compound that temporarily paralyzes them. “If a predator comes along in that window, it could be a natural control,” notes Tom. Gardeners can take advantage of this quirk by mixing geraniums into beds with more vulnerable plants.
Next, learn the difference between ladybugs vs Asian beetles.
About the Expert
Tom Tiddens works as the supervisor, plant health care, at the Chicago Botanic Garden. Tom is responsible for protecting the garden’s plant collections from diseases, pests and weeds in an environmentally sensitive manner.
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