By Lynn Ascrizzi
To many home gardeners, the common evening primrose (Oenothera biennis) may be little more than a weed. But, the tall native wildflower is a first line of defense when it comes to naturally controlling the pesky Japanese beetle.
This biennial plant is widely found in meadows, roadsides and neglected areas of the garden. In its first season, it produces only a stubby rosette. But, if second-year seedlings are allowed to thrive in convenient corners of your garden, they’ll grow into dramatic 5-to-6 foot tall plants whose bright-yellow flowers bloom from evening to early morning on central, branching stems.
Just when the evening primrose begins to flower, the Japanese beetle (Popillia japonica) emerges from beneath the soil, where it had overwintered as a large, white grub. Around the beginning of July in Maine, it appears on the garden scene as a full-blown beetle, ready to raise havoc.
As fate would have it, hordes of the stunning (but destructive), metallic-green and copper-colored beetles pop up just when roses begin to bloom and bush and pole beans wax tender and green. These are only a few of the hundreds of plants these garden marauders like to sink their mandibles into.
Yet, there’s something about the evening primrose that drives Japanese beetles to distraction. In fact, experienced gardeners report that the beetles actually prefer it over any other plant on their garden menu. There, they’ll congregate and mate by the dozens on its lemony scented flowers and lance-like leaves.
What better boon to the organic gardener than this natural beetle lure? No pheromone bait traps. No spun-bonded protective barriers. No toxic sprays.
Beetle management consists of visiting your primrose traps on a regular basis and dispatching the enemy in whatever manner of execution is preferred, such as knocking them into a coffee can, one-third full of soapy water. The cool of the morning is the best hour for picking beetles.
Persist in this eradication strategy and beetle ranks should noticeably reduce.
Another potent predator of the Japanese Beetle is the common chicken. Plant the primrose in the chicken run and watch them devour the enemy. Chickens absolutely LOVE Japanese beetles. I used to have lure traps and would empty them out for the chickens twice a day. Now I just planted the primrose in the run. This saves time and keeps the hens busy foraging through it. The beetles make the eggs especially orange and delicious. In the summer we don’t even buy feed anymore. See the action on our facebook site!