Q.Sunflower heads are not flowering
I am trying to find out why my sunflower heads are not flowering. Out of a dozen plants that came up, only one has actually flowered. Is there somewhere I can find pictures of what various pests do to sunflowers? I have tried to upload two pictures of the heads. Any hints would be greatly appreciated. Thank you in advance.
This is most likely due to the Sunflower Midge insect.
I would recommend you contact your County Extension Office to inquire on the best treatment in your region.
Here are some links for you with more information.