There is a type of coneflower that looks sort of like that. Offhand, I don't know the cultivar name or where to find a picture of it.

You'd know if you had the cultivar because you would have spent exdtra for it!

Some coneflower buds behave differently- although not quite as bizzare as yours! I'd remove it. Consider it a 'witches broom' a section of strange, gnarly growth on a shrub. I'd be worried that it may be a virus.

Your coneflowers have aster yellows, a viral disease. Pull any affected ones and dispose of them in the trash (do not compost).

I too have a mutated totally green coneflowers. The heads and petals are green. The same color of green too! The petals are very short, in fact the green head is the most prominate part of the flower. I planted these flowers by seed several years ago around a crape myrtle. This is the first year one of them mutated to all green. I plan on taking some pictures of them soon.

jancat, Marymd may be correct in her diagnosis - here is a link to a photo of a rudbeckia flower with aster yellows. Is this what your coneflower looks like?

Here is a link that might be useful: Aster yellows

The problem with the mutated coneflowers is Rose rosette virus. I have had coneflowers in my garden for years. This year I was hit by a bad outbreak of Rose rosette virus, which is carried by an eriophyid mite. I carried it from plant to plant on pruners. This year for the first time in 23 years of growing coneflowers I have had this very bad mutation on my coneflowers. This cannot be a coincidence. There is no cure. Dig up the bad plant and burn it or put in a sealed bag and dispose of it. When pruning roses or coneflowers clean pruners with alcohol between each plant.

I've had this for years with my Echincaeas--everything you've described and more! We thought it was just some sort of natural mutation, as we have a huge variety of Echinaceas.

But it's definitely "Aster Yellows". And all you can do is yank out the affected plant so it doesn't spread (and don't compost it) - the plant's definitely not going to get better

From Missouri Botanical Garden's site:

"Aster yellows" is a chronic, systemic plant disease caused by a bacterium-like organism called a phytoplasma.

Aster yellows is primarily transmitted by leafhoppers. When a leafhopper feeds on a plant infected with aster yellows it becomes "infected" with the phytoplasma and remains infected throughout its life.

The phytoplasma cells multiply and cause infection of the insectâÂÂs salivary glands within one to three weeks. When the infected insects feed on healthy plants, they inject the phytoplasma cells into the plant phloem. Susceptible plants will be symptomatic in 10 to 40 days.

Aster yellows phytoplasma is a difficult pathogen to control. Currently there is no cure for Aster yellows.Infected plants and weeds should be removed to eliminate that source of the phytoplasma and minimize spread. Unfortunately, this is the only control method that home gardeners have available.

Here is a link that might be useful: Missouri Botanical Garden's site