every year this happens to my coneflowers just before they bloom the heads...
every year this happens to my coneflowers just before they bloom the heads are cut about 1 inch down the stem from the bud. as in this picture. This year we planted some sunflowers for the grand kids and several of them are doing that also!! the sun flowers are breaking at about 5 -6 inches below the head
Sorry it has taken so long for someone to pick up your question and answer it. I was browsing through the unanswered questions and saw your image. This damage is typical of the sunflower headclipping weevil, Haplorhynchites aeneus. The headclipping weevil hits coneflowers pretty hard in some cases. Here are a couple of URLs with additional information: http://entomology.k-state.edu/extension/insect-information/crop-pests/sunflowers/sunflower-headclipping-weevil.html