If the spring weather is very cool and wet, I've had some blooms do this way on my Echinaceas. I found a photo of Alternaria stem rot that I've seen in some Echinacea. 'Tiki Torch' is especially prone to this. Did the blooms do like the ones in this photo?
I usually just cut the affected stalks back when I see this. Look for any spots on the leaves and remove the leaves with spots. They may be small and difficult to see. In early Spring if it is especially rainy and cloudy a spray with Daconil or other fungicide usually helps prevent the loss of blooms. Echinacea pallida also has this quite often. I used to spray it as a preventative measure every year. If Echinacea pallida gets this, you have to wait an entire year to see them bloom again. Luckily, some of the newer varieties will rebloom if they are treated. Here is a photo of the product I've used to prevent the loss of blooms in certain plants.
I hope this helps. I bet your weather was really cool and damp this spring. If it was, that is really what caused all your problems. I'd spray with Daconil next Spring when the plants come up before they start getting buds to bloom.
