Sounds like the Daylily but if you had them in previous years you would know this is what they do? so please could you be more specific as to which lily you have?

Hi Taylorsgarden, I think we'll need a photo to see what sort of lilies you've got & possibly get a clue or two about what's wrong. You can edit your question and add a photo, or two, or three.

Are they "real" lilies or day lilies? If they've been there for donkey's years they could be overcrowded and / or starving.

Slug pellets are not the only answer, though there are now environmentally friendly "organic" pellets available that are based on ferric phosphate. You could go out with a torch at night & pick them off and stamp on them (my preferred method) or you could use beer traps (a glass or dish of beer placed at soil level so the slugs can get in easily and drown.

I assume you've added the photos since the two responses posted above. This is indeed a hemerocalis, or day lily, so called because each flower only lasts a day. Looks quite healthy to me, but perhaps, if you've been having lots of rain as we have, the flowers have been spoiled more quickly by it.

I agree with Bamboo, they're day lilies and look as expected. Yours have a better colour than many, they often have "washed out orange" flowers.

Thanks for posting the picture Taylorsgarden. These lovely Daylillies do look overcrowded which can reduce the flowering, they need dividing (every 3-5 years) and you say they are several years old.

Many thanks we will try dividing them.

Not yet though?