This has been a strange year. I see the same thing on some of my lilies. I have had more bloom bust than I have ever seen. I am blaming it on the weather. We have had extreme heat dry conditions.
It is something about rain water vs home water with all the chemicals that are added to make it safe for drinking but toxic for plants when we did not get enough rain water to wash out the chemicals of home water.
I finally have gave up and decided to enjoy what I get this year. That is why I plant so many. If 5 do not bloom I will have 25 that will bloom.
