My flowering plants leaves are starting to turn yellow and brown. what is going on?

I have several plants. I don't know the names. They all have long skinney green leaves. I think some of them may be day lillies. They are all flowering, but in the last few days I have noticed that they are not looking very good. They are not as green as they should be. We just went through 2 100 degree days. I know they are getting enough water. What is going on and what do I do.

My flowering plants leaves are starting to turn yellow and brown. what is going on?
several things:





1) sun burn


2) too much fertilizer/not enough nutrients


3) diseases affecting the root
Reply:Have you used a fertilizer they don't need alot.It sounds like not enough water but you say they get plenty maybe cut back a day or two.Lilies can take the heat.