Help, my daffodils have gone white!

We planted lots of daffodils in our lawn about 10 years ago - 2 or 3 different varieties. We had a great display the first year, but since then more and more of them failed to flower. This year, however, we have a great display - the best ever. Except that they are all white! What can have happened? Is there anything I can do about it?

 

What a mystery! All i can think of is that the only variety that has survived out of the original selection is a white one and lacking any competition they have been able to thrive. Doesnt explain why they havnt flowered for ages. At least you have a lovely display this year. Enjoy.