It’s the time of year when we regularly go out and hunt for dangling flower heads, particularly on Purple Coneflowers, Rosinweed, Cup Plant, and Compass Plant. Unfortunately we are starting to see this kind of damage on other flowers like Black-Eyed Susan, Orange Coneflower, Green-headed Coneflower, and False Sunflower.

The damage is from the Sunflower Head-Clipping Weevil. Joe Boggs has a good article about the pest in “Coneflower Calamities” on the OSU Buckeye Yard and Garden onLine (BYGL) site. It is worth signing up for the weekly BYGL email newsletter.

Here is an example of the weevil’s work on a purple coneflower in our gardens.

The female weevil chews a ring of holes around the stem resulting in the flower dangling. The male and female mate on the dangling flowerhead then the female lays eggs in the dangling stem. The flowerhead eventually falls and the larvae completes the life cycle on the ground.

The only way to control the weevil is to remove the dangling part by cutting below where the damage is on the non-dangling stalk. The cutting should be put in a jar to contain and kill the eggs. Often we also nab the culprit weevil in the process, so the lid of the jar needs to stay on tight between cuts or the weevils will escape. Terri and I do this as a team with one of us cutting and the other opening and closing the jar. When done for the day we set the jar out in the sun to hasten the weevil’s demise.

Unfortunately, we have to keep this up for several days while the weevils are active. It’s a bit of a pain because it is tedious, repetitive, and easy to miss dangling heads. However, it needs to be done so the problem does not get progressively worse.