It may be a virus or something. All the primula family can do this sometimes. I just either leave it or nip off that flowerhead and wait for another to come through.

It's too early - I'm guessing the flower was initiated because of the mild winter, started to grow and then it got cold, meaning the flower stopped, right where it was - usual flowering time for these is April/May, though it does depend where you are and on weather conditions. Leave it alone - it may throw out more flowers later on anyway, or the stems on the existing ones will start to grow again.

Agree with Bamboo. Our denticulata are still in tight, resting buds and I expect them to be for a while. just leave it alone and it will probably produce more usual flowers in a couple of months time.

I have some white ones,that were exactly the same,but with the last few sunny days,the stems have now grown taller.only one flowerhead on each yet,but looking fine..More will appear before long,so I would just leave them..It's still very early days..

Yes, I have these and they are exactly the same...buds hugging the ground. It wil sort itself out in a few weeks, don't worry.

Thanks everyone, I will wait and see how they get on.