I’m not normally a violent person. And working in my garden usually helps me achieve an even more Zen-like state. But three summers ago when I discovered Japanese beetles feasting on my Frau Dagmar Hafstrup roses, I became an unrepentant murderer.
The Beetles—not music to my ears!
Japanese beetles have been spreading from the Eastern U.S. to the South and parts of the Midwest for the last 30 years. In Minnesota, where I garden, their populations have skyrocketed in the past decade thanks to perfect weather conditions, increased plantings of susceptible plants species and new housing developments with inviting soil.
Voracious and hardy
Adult Japanese beetles chow down in groups, consuming both the flowers and foliage of their favorite plants for about six weeks each summer. Their feeding frenzies can have devastating results. After mating, female beetles lay their eggs in the soil, and the grubs feed on grass roots in the fall and spring, seriously damaging lawns, nurseries and golf courses.
Waging war (unsuccessfully)
As an organic gardener, chemicals are not part of my arsenal (and frankly, they have a spotty record when it comes to defeating this pest). Instead, I spent the last two depressing summers knocking hordes of beetles off my roses into a bucket of soapy water three or four times a day. I managed to keep my roses alive, but murdering beetles does not make for a Zen-like gardening experience. And when the Japanese beetles devoured my 18-year-old North Star Cherry tree last summer, I knew I needed a different approach.
Don’t plant their favorite foods
According to the U.S. Department of Agriculture, these are the top 10 favorite landscape trees and shrubs for Japanese beetles:
- American Lindens
- Japanese Maples
- Norway Maples
- Crape Myrtles
- Pin Oaks
- Prunus species (plums, apricots, cherries and peaches)
The 60-ft. American Linden and two 20-year-old crabapples in my front yard are at the top of the “most susceptible” list (my now dead cherry tree was too). I’m not ready to chop down my remaining trees, but last fall, I decided to change my beetle-fighting strategy.
My radical solution—no more free lunch
I decided to get rid of all the plants in my yard that Japanese beetles love (even though I love those plants too). So I dug up all my beloved roses except the one the beetles had left alone. And I also chopped down my gorgeous grape vine, another beetle favorite. In their place, I planted Japanese beetle-resistant shrubs, vines and plants, including conifers, honeysuckle and ornamental grasses. Rose lovers will understand how radical this is, but it’ll be worth it if my garden becomes a beetle-free zone again.
A good friend called me a few days ago—this season’s Japanese beetles had arrived in her garden that very morning. I’ve been checking mine each day and so far, no beetles. I’ve got my fingers crossed (and my bucket ready!).
Your local extension service is the best source for which plants in your area are likely to be susceptible and resistant to Japanese beetles. For more information on Japanese beetle control measures.
For more information about how to combat pests indoor and out, check out these great articles: